JP2002158529A - Surface-mounted antenna structure and communications equipment provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy all the demands of band widening, miniaturizing and multi- banding. SOLUTION: A radiation electrode 3 is loop-shaped, an opening terminal 3a of this radiation electrode 3 is arranged opposite to a power feeding terminal side electrode portion via a gap, and a capacitor is formed between the opening terminal 3a and the power feed terminal side electrode portion. Since the interval between the resonance frequency of a fundamental mode and the resonance frequencies of a higher-order mode can be controlled variably by varying this capacitor, without markedly changing the resonance frequency in the fundamental mode of the radiating electrode 3, it is easy to design the respective resonance frequencies of the fundamental mode ands the higher-order mode, as demanded. Both the fundamental mode and the higher-order mode of the radiating electrode 3 can be utilized and multi-banding can be attained. Furthermore, an antenna 1 is mounted on a non-grounded area 16 of a mount board 15. Thus, both the widening of frequency band and miniaturizing of the antenna can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount antenna having a plurality of different frequency bands and a communication device having the same.

[0002]

2. Description of the Related Art FIG. 15 is a schematic perspective view showing an example of a surface mount antenna. The surface-mount type antenna 1 includes a base 2, a radiation electrode 3, a feed electrode 4, a first ground electrode 5, and a second ground electrode 6 formed on the surface of the base 2. ing.

As shown in FIG. 15, a power supply electrode 4 is formed on a base 2 from a bottom surface 2c to a top surface 2a via a side surface 2b, and first and second ground electrodes 5 and 6 are formed on the base 2 respectively. Like the power supply electrode 4, the power supply electrode 4 is formed on the upper surface 2 a from the bottom surface 2 c to the side surface 2 b so as to sandwich the power supply electrode 4. Further, on the upper surface 2a of the base 2, a radiation electrode 3 is connected at one end thereof to the first ground electrode 5, and an open end 3a at the other end is spaced from the second ground electrode 6. It is formed in a substantially U-shape that is arranged to face each other.

The antenna 1 shown in FIG. 15 has a bottom surface 2c of a base 2 as a mounting surface, for example, in a non-ground area (that is, an area where a ground electrode is not formed) of a circuit board of a communication device such as a portable telephone. Will be installed. A signal supply source 8 for supplying a signal to the power supply electrode 4 is provided on the circuit board. Further, when the antenna 1 is mounted on a set mounting area, the first
And a ground connection means for grounding each of the first and second ground electrodes 5 and 6 to the ground, and a connection means for connecting the power supply electrode 4 to the signal supply source 8 by a signal.

[0005] For this reason, the first antenna is mounted on a mounting area set on the circuit board, thereby providing the first antenna.
And the second ground electrodes 5 and 6 are grounded to the ground by the ground connection means, respectively, and the power supply electrode 4 is connected to the signal supply source 8.

For example, from the signal supply source 8 to the power supply electrode 4
Is supplied from the feed electrode 4 to the radiation electrode 3 by capacitive coupling, and the radiation electrode 3 performs an antenna operation due to the signal supply.

[0007]

Since the antenna 1 shown in FIG. 15 is mounted on the non-ground area of the mounting board (circuit board) as described above, it is easy to widen the frequency band and reduce the size. There is an advantage and an advantage that no matching circuit is required on the mounting substrate because no matching circuit is required. However, in recent years, one terminal has been using GSM (Global System for Mobile communication).
systems) and DCS (Digital Cellular system), P
DC (Personal Digital Cellular telecommunication
A multi-band compatible antenna capable of supporting a plurality of applications, such as a PHS (Personal Handyphone System) and a PHS (Personal Handyphone System), is required in the market. However, in the configuration of the antenna 1 shown in FIG. Has a problem in that it can only transmit or receive radio waves in one frequency band, and cannot meet the above-mentioned requirement for multi-band.

That is, the radiation electrode 3 has a plurality of resonance frequencies different from each other, and the lowest resonance frequency (basic resonance frequency) among the plurality of resonance frequencies.
And higher higher-order resonance frequencies cannot be independently variably controlled. For this reason, it is very difficult to design both the basic resonance frequency and the higher-order resonance frequency to be the required frequencies.

For this reason, in the antenna 1 shown in FIG. 15, for example, a resonance mode having a fundamental resonance frequency in the radiation electrode 3 (this is referred to as a fundamental mode in this specification) is used. Resonance mode (in this specification, this is called higher-order mode)
Is inevitably used, and as a result, as described above, only the transmission or reception of radio waves in one frequency band can be performed practically, and it is not possible to respond to the above-mentioned requirement for multi-band.

Meanwhile, a surface-mounted antenna 1 as shown in FIG. 16, which is different from the structure shown in FIG. 15, has also been proposed. In the antenna 1 shown in FIG.
A plurality of radiation electrodes 3 (3A, 3B) are provided such that one ends thereof are connected to a common power supply electrode 4, respectively.
The plurality of radiation electrodes 3 enable transmission or reception of radio waves in a plurality of different frequency bands. The antenna 1 shown in FIG. 16 is mounted, for example, on a ground electrode 11 of a circuit board 10 of a communication device.

As described above, the antenna 1 shown in FIG.
Since it is mounted on the ground electrode 11, a large capacitance is generated between the ground electrode 11 and the radiation electrodes 3 (3A, 3B), and there is a problem that the frequency bandwidth is narrowed due to the capacitance. . To avoid this problem,
The thickness of the base 2 must be increased to reduce the capacitance between the radiation electrode 3 and the ground, and there is a problem that the antenna 1 becomes large. Thus, it is difficult for the antenna 1 shown in FIG. 16 to achieve both a wide band and a small size.

In addition to the above, various types of surface-mount antennas have been proposed. In any of the proposed antennas, a wide frequency band, a small antenna, and a multi-band antenna have been proposed. Not all requirements can be met satisfactorily.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to broaden a frequency band,
An object of the present invention is to provide a surface-mounted antenna structure capable of easily satisfying all requirements for miniaturization and multi-band antennas, and a communication device including the same.

[0014]

Means for Solving the Problems In order to achieve the above object, the present invention has the following structure to solve the above problems. That is, in the first invention, an antenna in which a radiation electrode is formed on a base and a power supply electrode for supplying a signal to one end of the radiation electrode is mounted on a mounting substrate, and the antenna is formed from a power supply electrode. A fundamental mode antenna operation and a higher mode antenna operation of the radiation electrode can be performed according to the supplied signal, and the surface radiation type antenna structure has a plurality of different frequency bands from each other. One end of the radiation electrode forms a power supply end connected to the power supply electrode, the other end forms an open end, and the radiation electrode has a higher mode resonance frequency between the open end and the power supply end side electrode portion. An outer loop-shaped radiating electrode having a capacitance for controlling is formed, a non-ground area is formed on the mounting board, and the antenna is mounted on a non-ground area of the mounting board. hand And a means for solving the problem with a configuration that.

According to a second aspect of the present invention, there is provided the configuration according to the first aspect of the present invention, wherein the loop-shaped radiation electrode is provided with a meander electrode portion for providing an inductance to a large current distribution region. Have been.

According to a third aspect of the present invention, there is provided the configuration of the first or second aspect, wherein a power supply electrode is formed on a side surface of the base, a loop-shaped radiation electrode is formed on the upper surface of the base from the power supply electrode, and In this configuration, a loop path is formed to return to the top surface by sequentially passing the side surface, the mounting bottom surface, and the side surface from the top surface of the base body and returning to the top surface, forming a capacitance between the open end and the power supply end side electrode portion. The feature is that it is.

According to a fourth aspect of the present invention, there is provided the first, second or third aspect.
The antenna base is provided with a plurality of radiating electrodes including a loop-shaped radiating electrode provided by connecting their respective feeding ends to a common feeding electrode. I have.

According to a fifth aspect of the present invention, there is provided the configuration of any one of the first to fourth aspects of the present invention, wherein a power supply wiring pattern connected to a power supply electrode of the antenna is formed on the mounting board. A sub-feeding wiring pattern having an inductance for adjusting a resonance frequency is formed toward the base by branching off from the feeding wiring pattern, and communicates with the base of the antenna via the feeding electrode to the feeding wiring pattern. A radiation electrode to be connected is formed, and another radiation electrode connected to the sub-feeding wiring pattern is formed.

According to a sixth aspect of the present invention, there is provided the structure of any one of the first to fifth aspects of the present invention, wherein the base of the antenna includes a region of the loop-shaped radiating electrode where the higher-order mode electric field is strongest, the ground, and the ground. And a ground electrode for providing a capacitance between them.

According to a seventh aspect of the present invention, there is provided the configuration according to any one of the first to sixth aspects, wherein the antenna is mounted on a mounting substrate by soldering, and the base is provided with the solder. It is characterized in that an electrode dedicated to solder fixing for bonding to a base is formed.

According to an eighth aspect of the present invention, there is provided the configuration according to any one of the first to seventh aspects of the present invention, wherein a power supply wiring pattern is formed on the mounting board so as to communicate with a power supply electrode of the antenna. The power supply wiring pattern is provided with an inductor portion for providing an inductance.

According to a ninth aspect of the present invention, the antenna according to any one of the first to eighth aspects is provided, wherein the base of the antenna has a rectangular parallelepiped shape, and a plurality of radiation electrodes including a loop-shaped radiation electrode are provided. It is configured to be formed on the surface of the base, and the plurality of radiation electrodes are provided so that the formation surface of the base is different from each other.

The communication device according to a tenth aspect of the present invention is the communication device according to the first to ninth aspects.
The surface-mounted antenna structure according to any one of the inventions, wherein the mounting substrate of the surface-mounted antenna structure is constituted by a circuit board of a communication device, and the antenna is provided at a corner area of the circuit board with a radiation electrode. And the current flowing in the ground region of the circuit board are strengthened and arranged so as to satisfy the condition of having directivity.

In the invention having the above structure, the antenna is mounted on the non-ground area of the mounting board, and the radiation electrode of this antenna has a loop-shaped radiation electrode whose open end is opposed to the feeding end side electrode portion with a space therebetween. And an electrode. As described above, in the present invention, since the antenna is mounted on the non-ground area of the mounting board, the frequency band can be broadened,
Further, miniaturization of the antenna is facilitated.

As described above, the open end of the loop-shaped radiation electrode is opposed to the power supply end side electrode portion of the radiation electrode (that is, the region where the current distribution in the fundamental mode is the largest) with an interval therebetween. And has a large capacitance between the open end and the power supply end side electrode portion. By changing the capacitance, the interval between the resonance frequency of the fundamental mode and the resonance frequency of the higher-order mode can be variably controlled without greatly changing the resonance frequency of the fundamental mode of the loop-shaped radiation electrode.

Thus, it is easy to design so that each of the resonance frequencies of the fundamental mode and the higher-order mode becomes the required frequency, and it is possible to use both the fundamental mode and the higher-order mode of the loop-shaped radiation electrode. Can be done. For this reason, by providing the loop-shaped radiation electrode, transmission or reception of radio waves in a plurality of different frequency bands can be performed while achieving a wider band and a smaller size, and it is possible to cope with multi-band.

As described above, the provision of a unique configuration in the present invention makes it easy to satisfy all the demands for broadband, miniaturization, and multiband.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a specific surface-mounted antenna structure extracted from the communication device of the first embodiment, and FIG. 2 shows an antenna of the communication device of the first embodiment. Are schematically shown.

A characteristic of the first embodiment is that the radiation electrode 3 of the surface-mount type antenna 1 is formed in an outer loop shape as shown in FIG. 1, and as shown in FIG. A non-ground area 16 (that is, an area where the ground electrode 17 is not formed) is formed in a corner area of the circuit board 15 of the communication device, and the antenna 1 is mounted in the non-ground area 16. There are various configurations of the communication device, and any configuration other than the above-described configuration characteristic in the first embodiment may be adopted, and the description thereof will be omitted here.

That is, as shown in FIG. 1, the surface-mounted antenna structure shown in the first embodiment includes a surface-mounted antenna 1 and a circuit board (mounting board) of a communication device on which the antenna 1 is mounted. The antenna 1 includes a rectangular parallelepiped base 2 made of a dielectric or magnetic substance, and a loop-shaped radiation electrode 3 and a feed electrode 4 formed on the base 2. Have been.

The power supply electrode 4 is formed from the bottom surface 2c to the side surface 2b of the base 2, and is formed toward the upper surface 2a through a lateral edge region of the side surface 2b. The loop-shaped radiation electrode 3 is formed such that a region near each side of the rectangular upper surface 2a from the power supply electrode 4 is formed in a loop along each side, and the open end 3a of the loop-shaped radiation electrode 3 is The open end 3a is opposed to the power supply end side electrode portion with a space therebetween.
A capacitance is generated between the power supply end side electrode portion and the power supply end side electrode portion.

In the example shown in FIG. 1, the open end 3a
An overhanging electrode portion 18 is formed at the power supply end side electrode portion opposed to the electrode at an interval.

In the first embodiment, as described above,
As shown in FIG. 2, the circuit board 15 has a non-ground area 16 formed in a corner area.
The antenna 1 is mounted on the base 6 by a fixing means such as solder, using the bottom surface 2c of the base 2 as a mounting bottom surface. At this time, the antenna 1 is arranged such that a longitudinal direction of a portion A of the radiation electrode 3 shown in FIG. 1 (that is, a portion formed along the long side a of the rectangular upper surface 2a of the base 2) and a circuit The current Im flowing through the radiation electrode 3 as shown in FIG.
Is mounted on the non-ground area 16 of the circuit board 15 under the condition that the current Ig flowing through the ground electrode 17 strengthens. Thereby, on the lower side of the non-ground area 16,
Even if parts such as speakers are arranged, the influence of the parts can be reduced. Further, in the first embodiment, the antenna 1 has the power supply electrode 4 disposed on the upper edge side of the circuit board 15 shown in FIG. 2, thereby having a strong directivity in the direction of the arrow α. Can be made.

As described above, the antenna 1 is connected to the circuit board 15
, The power supply electrode 4 of the antenna 1 is connected to the signal supply source 8 formed on the circuit board 15 by a signal.
When a signal is supplied from the signal supply source 8 to the power supply electrode 4, the signal is transmitted from the power supply electrode 4 to the radiation electrode 3,
In accordance with the signal, the radiation electrode 3 performs each antenna operation in the fundamental mode and the higher order mode. Note that the reference symbol L shown in FIG.
Reference numerals 1 and L2 denote matching circuit inductances used to match the antenna 1 to the signal supply source 8, respectively.

According to the first embodiment, the antenna 1
Is mounted on the non-ground area 16 of the circuit board 15, so that it is easy to achieve both miniaturization and broadband of the antenna 1. That is, if it is assumed that the antenna 1 is mounted on the ground electrode 17 of the circuit board 15, the radiation electrode 3 and the ground electrode 17
Because the distance between them is narrow, the radiation electrode 3 and the ground electrode 1
There is a problem that the capacity between the capacitors 7 greatly affects the frequency bandwidth and the frequency bandwidth becomes narrow. In order to avoid this, the base 2 is made thick to increase the distance between the radiation electrode 3 and the ground electrode 17, thereby reducing the capacitance between the radiation electrode 3 and the ground electrode 17 so as to reduce the frequency band. It is conceivable to reduce the effect of the capacitance between the radiation electrode 3 and the ground electrode 17 described above. However, since the thickness of the base 2 is increased as described above, there is a problem that the antenna 1 becomes large. As described above, when the antenna 1 is mounted on the ground electrode 17, it is difficult to improve both the miniaturization and the broadband of the antenna 1.

On the other hand, in the first embodiment,
As described above, since the antenna 1 is formed in the non-ground area 16 of the circuit board 15, the distance between the radiation electrode 3 and the ground electrode 17 is widened, so that the capacitance between the radiation electrode 3 and the ground electrode 17 is small. As a result, the influence on the frequency bandwidth can be suppressed small,
It is easy to improve both the miniaturization and the broadband of the antenna 1.

Further, according to the first embodiment, the radiation electrode 3 is formed in a loop shape, and its open end 3a is opposed to the power supply end side electrode portion at an interval to form a capacitor. Because of the shape, the path length of the radiation electrode 3 can be increased without increasing the size of the base 2, and the resonance frequency of the fundamental mode can be reduced. In addition, since the power supply end side electrode portion of the radiation electrode 3 has a large current distribution, the capacity between the power supply end side electrode portion and the open end 3a is strong, and the power supply end side electrode portion is large. The distance Δf between the resonance frequency f1 of the fundamental mode and the resonance frequency f2 of the higher-order mode is largely variably controlled without changing the resonance frequency f1 of the fundamental mode largely by varying the capacitance between the resonance frequency f1 and the open end 3a. Can be.

This has been confirmed by experiments performed by the present inventors. The results of the experiment are shown in FIGS. The following can be seen from the results of this experiment. For example, the open end 3a of the loop-shaped radiation electrode 3 is located closer to the power supply end side electrode portion than in the case where the loop-shaped radiation electrode 3 is configured to have a frequency characteristic as shown in FIG. When the capacitance between the open end 3a and the power supply end side electrode portion is increased by approaching, as shown in FIG. Higher order mode resonance frequency f2
The interval Δf ′ is the state (Δf) shown in FIG.
Narrower than.

Contrary to the above, the open end 3a is farther from the power supply end side electrode portion than the loop-shaped radiation electrode 3 having the frequency characteristic shown in FIG. In the case where the capacitance between the loop-shaped radiating electrode 3 and the power feeding end side electrode portion is reduced, as shown in FIG. The interval Δf ″ between f2 is the same as that in FIG.
Is wider than the state (Δf) shown in FIG.

As shown in FIGS. 3A to 3C, by changing the capacitance between the open end 3a of the loop-shaped radiation electrode 3 and the power supply end side electrode portion, the radiation electrode 3 is formed.
The resonance frequency f2 of the higher-order mode can be largely variably controlled without greatly changing the resonance frequency f1 of the fundamental mode. In other words, the variable frequency control between the open end 3a of the radiation electrode 3 and the power supply end side electrode portion allows the higher mode resonance frequency f2 to be substantially independent of the fundamental mode resonance frequency f1. Variable control becomes possible.

Thus, the resonance frequency f1 of the fundamental mode
And the resonance frequency f2 of the high-order mode can be easily designed to be the required frequency. For this,
By causing the loop-shaped radiation electrode 3 to perform each of the antenna operations in the fundamental mode and the higher-order mode, it is possible to transmit or receive radio waves in a plurality of desired frequency bands. In the configuration shown in FIG. 16 shown in the conventional example, a plurality of radiation electrodes 3A and 3B are formed on the upper surface of the base 2 so that the antenna 1 has a plurality of different frequency bands. Accordingly, it is necessary to form the base 2 large, and the antenna 1
However, in the configuration of the first embodiment, only one loop-shaped radiation electrode 3 is formed, and as described above, the basic mode and the higher-order mode of the loop-shaped radiation electrode 3 can be reduced. A plurality of mutually different frequency bands can be provided by each antenna operation. This can suppress an increase in the size of the antenna 1.

As described above, by providing the specific configuration in the first embodiment, the antenna 1 which can cope with the multi-band operation while achieving a wider band and a smaller size, and the antenna 1 are provided. An epoch-making effect that a communication device can be provided can be achieved.

In the above experiment, by changing the distance between the open end 3a of the radiation electrode 3 and the power supply end side electrode portion, the capacitance between the open end 3a and the power supply end side electrode portion was changed. However, by changing the width of the open end 3a, the capacitance between the open end 3a and the power supply end side electrode portion may be variably controlled, or the open end 3a and the power supply end side electrode may be variably controlled. The capacitance between the open end 3a and the power supply end side electrode part may be variably controlled by changing both the interval between the parts and the width of the open end 3a. In the first embodiment, the overhanging electrode portion 18 is formed at the power supply end side electrode portion facing the open end 3a with a space therebetween.
The overhanging electrode 18 can increase the capacity between the open end 3a and the power supply end side electrode portion, and can approach the resonance frequency in the fundamental mode to the resonance frequency in the higher order mode.

Further, in the first embodiment, the antenna 1 is mounted in a corner area of the circuit board 15, and the portion A of the loop-shaped radiation electrode 3 shown in FIG.
The current distribution is larger than the side region.
And the longitudinal direction of the ground electrode 17 of the circuit board 15 are matched, and the current Im of the radiation electrode 3 and the current Ig flowing through the ground electrode 17 are strengthened.
Since the antenna 1 is mounted in a corner area of the circuit board 15, the ground electrode 17 greatly contributes to the directivity of the antenna 1, and the direction shown by the arrow α shown in FIG. 15 (a width direction orthogonal to the longitudinal direction) can be provided to the antenna 1.

In an omnidirectional antenna, for example, when an object that can be regarded as ground moves relatively near or far from the antenna, the antenna characteristic changes due to the movement of the object. This causes a problem that the reliability of the antenna is reduced. On the other hand, in the first embodiment, as described above, the antenna 1 can be provided with a strong directivity. Therefore, the antenna characteristic due to the movement of an object that can be regarded as ground due to the strong directivity is obtained. Can be suppressed, and the reliability of the antenna characteristics of the antenna 1 and the communication device including the antenna 1 can be improved.

Further, in the first embodiment, as described above, the variable control of the capacitance between the open end 3a of the loop-shaped radiation electrode 3 and the power supply end side electrode portion allows the loop-shaped radiation electrode 3 to be controlled. Since the resonance frequency f2 of the higher-order mode can be variably controlled without greatly changing the resonance frequency f1 of the fundamental mode, for example, the resonance frequency f2 of the higher-order mode is shifted in a direction lower than the set frequency. In this case, for example, the open end 3a of the radiation electrode 3 is trimmed to reduce the capacitance between the open end 3a and the power supply end side electrode portion, and the resonance frequency f2 of the higher mode is increased to set the frequency. It is possible to match. For this reason, the resonance frequency f2 of the higher-order mode is formed in advance so as to be slightly lower than the set frequency, and the resonance frequency f2 is adjusted by trimming or the like in the manufacturing process as described above. Then, the antenna 1 having the set higher-order mode resonance frequency f2 can be obtained with almost no adverse effect on manufacturing accuracy.

In the first embodiment, since the open end 3a of the radiation electrode 3 is formed on the upper surface 2a of the base 2, the resonance frequency f2 due to the above-described trimming is obtained.
In the case of adjusting the frequency, the work of the frequency adjustment becomes easy.

Hereinafter, a second embodiment will be described.

The characteristic feature of the second embodiment is that a meander electrode section 20 is provided in the large current distribution area A of the loop-shaped radiation electrode 3 as shown in FIG. The other configuration is almost the same as that of the first embodiment. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the overlapping portions of the common portions will be described. Description is omitted.

In the second embodiment, as described above,
A meandering electrode portion 20 is provided in the loop-shaped radiation electrode 3 in the large current distribution region A, and the meandering electrode portion 20 is provided.
Thereby, an inductance can be provided to the large current distribution side region A. Thereby, the electric length in the large current distribution region A can be increased, and the resonance frequency of the fundamental mode of the loop-shaped radiation electrode 3 can be reduced. When the resonance frequency of the fundamental mode of the loop-shaped radiation electrode 3 is to be reduced without providing the meander electrode portion 20 as described above, for example, in order to increase the path length of the loop-shaped radiation electrode 3, Needs to be increased, which causes a problem that the antenna 1 is increased in size. On the other hand, as shown in the second embodiment, by providing the meander electrode portion 20 in the loop-shaped radiation electrode 3, the loop-shaped radiation electrode 3 can be formed without increasing the size of the base 2.
It is possible to lower the resonance frequency of the fundamental mode.

In particular, in the second embodiment, as described above, the meander electrode portion 20 is provided in the large current distribution region A of the loop-shaped radiation electrode 3. Since the change in the resonance frequency of the fundamental mode of the loop-shaped radiation electrode 3 with respect to the change in the electric length in the large current distribution region is larger than when changing the electric length in the other regions, the second embodiment is used. As shown in the example, the resonance frequency of the loop-shaped radiation electrode 3 can be effectively reduced by providing the meander electrode portion 20 in the large current distribution region A of the loop-shaped radiation electrode 3.

The electrode width, the number of detours, the pitch, and the like of the meander electrode section 20 are variably set in accordance with various conditions such as a required resonance frequency.
However, the present invention is not limited to the form shown in FIG.

Hereinafter, a third embodiment will be described. The characteristic feature of the third embodiment is that the loop-shaped radiation electrode 3 is formed as shown in FIG. Other configurations are substantially the same as those of the above-described embodiments. In the description of the third embodiment, the same components as those of the above-described embodiments are denoted by the same reference numerals, and the description of the common portions will not be repeated. Omitted.

As shown in FIG. 5, in the third embodiment, the power supply electrode 4 is formed on the side surface 2b of the rectangular parallelepiped base 2, and the loop-shaped radiation electrode 3 is separated from the power supply electrode 4 by the base 2 Formed on the upper surface 2a of the base 2, and further formed with a loop path returning to the upper surface 2a from the upper surface 2a of the base 2 through the side surface 2e, the mounting bottom surface 2c, and the side surface 2f in order.
The open end 3a of the loop-shaped radiation electrode 3 is opposed to the power supply end side electrode portion with an interval.

In the example shown in FIG. 5, the width H of the electrode portion formed on the base upper surface 2a on the open end 3a side of the loop-shaped radiation electrode 3 is wider than other regions. For this reason, the configuration is such that the capacitance between the open end 3a and the power supply end side electrode portion can be increased as compared with the case where the loop-shaped radiation electrode 3 has the same width over the entire length.

According to the third embodiment, since the loop-shaped radiating electrode 3 has a loop-shaped configuration as shown in FIG. Even if the object to be considered moves relatively far and near with respect to the circuit board 15, a change in antenna characteristics due to the movement of the object can be suppressed.

This is because the loop-shaped radiating electrode 3 has a loop-like form as shown in FIG. 5, that is, the loop-shaped radiating electrode 3 extends along a plane orthogonal to the substrate surface of the circuit board 15. The electric field E based on the current flowing through the loop-shaped radiation electrode 3 is oriented perpendicular to the substrate surface of the circuit board 15 as shown in FIG. Even if the object regarded as ground moves relatively far and near with respect to the circuit board 15 in the direction of the electric field E, the change of the electric field E with respect to the movement of the object can be very small. When the electric field E changes, the current of the loop-shaped radiation electrode 3 changes, and the antenna characteristics change. In the third embodiment, the object moves in the direction of the electric field E as described above. Even if the object moves relatively to or away from the circuit board 15, the electric field E hardly changes, and the current distribution of the loop-shaped radiation electrode 3 does not change much. The change can be suppressed small. Therefore, it is possible to prevent the antenna efficiency from deteriorating due to the movement of the object.

When the characteristic configuration of the third embodiment is combined with the specific configuration of the second embodiment, for example, in the loop-shaped radiation electrode 3 shown in FIG. The radiating electrode portion (current distribution large side region) formed on the mounting bottom surface 2c is a meander electrode portion as shown in the second embodiment. With such a configuration, the effect shown in the second embodiment (that is, the effect that the antenna 1 can be further downsized) and the third embodiment can be obtained. (I.e., the effect of suppressing a change in antenna characteristics due to the distance movement of an object regarded as ground) can be achieved.

Hereinafter, a fourth embodiment will be described. The characteristic feature of the fourth embodiment is that, as shown in FIGS. 6, 7 and 8, in addition to the loop-shaped radiation electrode 3, a radiation electrode 22 different from the loop-shaped radiation electrode 3 is provided on the base 2 It is provided in. Other configurations are almost the same as those of the above embodiments, and in the description of the fourth embodiment,
The same reference numerals are given to the same components as those in the above embodiments,
A duplicate description of the common part is omitted.

In the example shown in FIG. 6, the loop-shaped radiation electrode 3 has the form shown in the first embodiment, is formed on the upper surface 2a of the base 2, and the radiation electrode 22 is The power supply electrode 4 on the side surface 2b is formed on the side surface 2d via the side surface 2e. As described above, the radiation electrode 22 is formed on the surfaces 2 e and 2 d of the base 2 different from the loop-shaped radiation electrode formation surface 2 a of the base 2.

In the example shown in FIG. 7, the loop-shaped radiation electrode 3 has the form shown in the third embodiment. The radiation electrode 22 is formed from the feeding end of the loop-shaped radiation electrode 3 in parallel with the open end 3a side of the loop-shaped radiation electrode 3 with an interval therebetween. The electrode 3 is connected to the power supply electrode 4 via the power supply end.

In the example shown in FIG. 8, the first
A loop-shaped radiation electrode 3 similar to that shown in the embodiment is formed, and another radiation electrode 22 is formed. The radiation electrode 22 shown in FIG. Unlike the electrode 22, the power supply end is not connected to the power supply electrode 4. In the example shown in FIG. 8, a power supply wiring pattern 25 connected to the power supply electrode 4 is formed on the circuit board 15, and a sub power supply wiring pattern 26 connected to the radiation electrode 22 is provided on the circuit board 15. The loop-shaped radiation electrode 3 branches off from the wiring pattern 25 and is formed via a phase circuit (phase control chip component 28).
Numerals 2 are each connected to a common power supply wiring pattern 25 via a sub power supply wiring pattern 26. Reference numeral 27 in FIG. 8 indicates a matching chip coil component, and reference numeral 29 indicates a phase control chip component.

The sub-feeding wiring pattern 26 shown in FIG. 8 has an inductance, and the resonance frequency of the radiation electrode 22 can be variably adjusted by changing the magnitude of the inductance. Further, by changing the constant of the phase circuit (the phase control chip components 28 and 29 in the example shown in FIG. 8) connected to the sub-feeding wiring pattern 26, the mutual connection between the loop-shaped radiation electrode 3 and the radiation electrode 22 can be achieved. The effect can be reduced.

According to the fourth embodiment, since the radiating electrode 22 different from the loop-shaped radiating electrode 3 is provided on the base 2, the antenna operation of the loop-shaped radiating electrode 3 in the basic mode and the antenna of the higher-order mode are performed. In addition to the operation, the antenna operation by the radiation electrode 22 is performed, so that transmission or reception of radio waves in more frequency bands becomes possible. Accordingly, it is possible to cope with three or more different applications only by providing one chip-shaped antenna 1, and it is possible to further promote multiband.

As shown in FIG. 6 and FIG. 8, the loop-shaped radiation electrode 3 and the radiation electrode 22 are formed on different surfaces of the base 2 respectively, so that the loop-shaped radiation electrode 3 and the radiation electrode 22 are formed. Mutual interference can be further suppressed. Therefore, for example, in order to prevent mutual interference between the loop-shaped radiation electrode 3 and the radiation electrode 22, it is necessary to take a measure such as enlarging the base 2 to increase the interval between the loop-shaped radiation electrode 3 and the radiation electrode 22. Therefore, the size of the antenna 1 can be reduced.

The form of each of the loop-shaped radiation electrode 3 and the radiation electrode 22 is not limited to the examples shown in FIGS. 6 to 8. A meander electrode unit similar to that shown in the second embodiment may be provided in the large current distribution side region of the loop-shaped radiation electrode 3 shown in the example.

Hereinafter, a fifth embodiment will be described. What is characteristic in the fifth embodiment is that the fifth embodiment is provided with a specific configuration for making it easier to variably control the resonance frequency f2 of the higher order mode of the loop-shaped radiation electrode 3. That is, in the fifth embodiment, the ground electrode 30 is formed on the base 2 of the antenna 1 as shown in FIG. The other configuration is almost the same as that of each of the above-described embodiments. In the description of the fifth embodiment, the same components as those of the above-described embodiments are denoted by the same reference numerals, and the description of the common portions will not be repeated. Omitted. Reference numeral 32 in FIG. 9 indicates a matching chip coil component.

The resonance frequency of the radiation electrode can be variably controlled by forming a capacitance between the open end of the radiation electrode and the ground and varying the capacitance between the open end and the ground. Further, as described in the above embodiments, when the radiation electrode is formed as the loop radiation electrode 3, the strongest electric field portion of the higher order mode in the loop radiation electrode 3 is, for example, a broken line B in FIG. (That is, in the example shown in FIG. 9, the upper surface 2 of the base 2)
a, the open end of the loop-shaped radiation electrode 3 in the higher-order mode is apparently the electric field strongest part B, and the loop-shaped portion in the higher-order mode. The open end of the radiation electrode 3 is located at a position different from the open end 3a of the loop-shaped radiation electrode 3 in the basic mode.

The present inventor pays attention to this, and forms a capacitance between the open end of the loop-shaped radiation electrode 3 and the ground in the higher-order mode, and varies the capacitance to thereby form the loop-shaped radiation electrode 3. Resonance frequency f1 of the fundamental mode
Have been devised so that the resonance frequency f2 of the higher-order mode can be variably controlled without substantially changing.

That is, in the fifth embodiment, the ground electrode 30 capable of forming a capacitance between the highest-order mode electric field portion (open end of the higher-order mode) of the loop-shaped radiation electrode 3 and the base electrode 30 is provided. 2 is formed.

Specifically, for example, in the example shown in FIG.
The ground electrode 30 includes a side surface 2f of the base 2 and a side surface 2f.
b at the right corner of the bottom side. Also,
In the example shown in FIG. 9, a capacitance is formed also at the center of the bottom surface side of the side surface 2 b of the base 2, that is, with the region in the vicinity of the strongest electric field portion B of the higher order mode in the loop radiation electrode 3. The ground electrode 30 is also provided at a position where the power supply can be performed.

In other words, in the example shown in FIG. 9, between the loop-shaped radiation electrode 3 and the electric field strongest region surrounded by the chain line Z in FIG. The ground electrode 3 is formed so that a capacitance is formed.
0 is formed.

The circuit board 15 is formed with a ground wiring pattern 33 for connecting and connecting the ground electrode 17 and the ground electrode 30 to each other.
0 is electrically connected to the ground electrode 17 via the ground wiring pattern 33 and is grounded to the ground. For this reason, the ground electrode 30 has a configuration in which a capacitance is formed between the high-order mode electric field strongest region Z in the loop-shaped radiation electrode 3 and the ground.

In the fifth embodiment, the ground electrode 30 is connected to the ground wiring pattern 33 via solder.
The base 2 can be fixed to the circuit board 15 by the above-mentioned solder. That is, as described above, the ground electrode 30 not only has a function of forming a capacitance between the electric field strongest side region Z of the higher-order mode in the loop-shaped radiation electrode 3 and the ground, but also has a function of soldering the base 2 to the circuit board by soldering. It also functions as a fixing electrode for fixing to 15.

As described above, the base 2 can be fixed to the circuit board 15 by the solder between the ground electrode 30 and the ground wiring pattern 33. In the fifth embodiment, the base 2 of the antenna 1 is Strongly circuit board 1
For example, as shown in FIG. 9, a fixing electrode 31, which is an electrode dedicated to solder fixing, is provided to fix the fixing electrode 5 to the fixing electrode 5.
The fixing electrode 31 is connected to the ground electrode 1 of the circuit board 15.
7 and electrodes not connected to other conductors such as the loop-shaped radiation electrode 3 on the base 2.

In the example shown in FIG. 9, the fixing electrodes 31 are provided at a plurality of positions, and each of the fixing electrodes 31 is different from the surface of the base 2 on which the fixing electrodes 31 are formed (that is, the surface is different from the surface on which the fixing electrodes 31 are formed). (2 places on the left and right bottom side corners of the side 2d)
It is provided in.

As described above, the fixing electrode 31 is provided.
Using the fixing electrode 31 and the ground electrode 30,
By fixing the base 2 to the circuit board 15 by soldering, it is possible to more reliably prevent the antenna 1 from peeling off the circuit board 15 when an impact is applied to the communication device due to, for example, a drop of the communication device. And the reliability of the durability of the communication device can be increased.

According to the fifth embodiment, the ground electrode 30 for providing a capacitance between the high-order mode electric field strongest region Z in the loop-shaped radiation electrode 3 and the ground is provided. Therefore, the loop-shaped radiation electrode 3
, The capacitance between the strongest electric field region of the higher-order mode (that is, the open end side of the higher-order mode) and the ground electrode 30 (that is, the ground) is changed in a direction in which the capacitance is increased. Of the higher-order mode without substantially changing the resonance frequency f1 of the fundamental mode.
2 can be variably controlled in a downward direction. Conversely, by changing the capacitance between the region of the loop-shaped radiation electrode 3 in the higher-order mode electric field strongest region and the ground electrode 30 in a direction to decrease the resonance frequency of the loop-shaped radiation electrode 3 in the fundamental mode. It is possible to variably control the resonance frequency f2 of the higher-order mode to be higher without changing f1 almost.

As described above, by providing the ground electrode 30 and changing the capacitance between the region of the loop-shaped radiation electrode 3 where the higher-order mode electric field is strongest and the ground electrode 30, the loop-shaped radiation electrode 3 is formed. The resonance frequency f2 of the higher-order mode can be variably controlled without substantially changing the resonance frequency f1 of the fundamental mode.
It becomes much easier to design so that 1 and f2 are the required frequencies.

In the example shown in FIG. 9, the loop-shaped radiation electrode 3 has the form shown in the first embodiment, but the loop-shaped radiation electrode 3 has the form shown in the second embodiment. Even in the case of the embodiment 4, the same effect as described above can be obtained by providing the ground electrode 30 at the same position as the above on the base 2.

When the loop-shaped radiation electrode 3 has the form as shown in FIG. 5 shown in the third embodiment, the region where the electric field of the higher-order mode in the loop-shaped radiation electrode 3 is the strongest (the higher-order mode) (Open end side) is an electrode portion surrounded by a broken line Z in FIG. 5, so that the ground electrode 30 is disposed at a position where a capacitance can be formed between the electrode portion and the strongest electric field side region Z. Thereby, the same effect as described above can be obtained.

Further, as shown in the fourth embodiment, while the loop-shaped radiation electrode 3 is formed on the base 2,
When another radiation electrode 22 is formed, similarly to the above,
By arranging the ground electrode 30 at a position where a capacitance can be formed between the loop-shaped radiation electrode 3 and the higher-order mode electric field strongest region, the same effect as described above can be obtained.

Hereinafter, a sixth embodiment will be described. The feature of the sixth embodiment is that, as shown in FIG. 10, the power supply wiring pattern 25 formed on the circuit board 15 includes chip coil components 34 and 35 as inductor portions.
Is connected. Other configurations are the same as those of the above-described embodiments. In the description of the sixth embodiment, the same components as those of the above-described embodiments are denoted by the same reference numerals, and the overlapping description of the common portions will be omitted. I do.

In the sixth embodiment, as shown in FIG. 10, a power supply wiring pattern 25 for electrically connecting the power supply electrode 4 and the signal supply source 8 is formed on the circuit board 15. In the wiring pattern 25 for use, a dividing portion 25a is formed by a gap. The power supply wiring pattern portions at both ends of the dividing portion 25 are conductively connected by the chip coil component 34. One end of the chip coil component 35 is connected to the power supply wiring pattern 25 at a position on the tip side of the mounting position of the chip coil component 34, and the other end of the chip coil component 35 is electrically connected to the ground electrode 17. It is connected.

According to the sixth embodiment, since the chip coil components 34 and 35 are connected to the power supply wiring pattern 25, the chip coil components 34 and 35 provide inductance to the power supply wiring pattern 25. As a result, the electrical length of the power supply wiring pattern 25 can be increased. The amount of current flowing through the power supply wiring pattern 25 is larger than the amount of current flowing through the loop-shaped radiation electrode 3.
By providing an inductance to the power supply wiring pattern 25 having a large amount of current to increase the electrical length, the resonance frequency f1 of the fundamental mode of the loop radiation electrode 3 can be reduced without changing the size of the base 2. Can be lowered effectively. This facilitates downsizing of the antenna 1.

Further, the magnitude of the inductance applied to the power supply wiring pattern 25 can be easily varied by the chip coil components 34 and 35, and the magnitude of the inductance applied to the power supply wiring pattern 25 as described above. , The resonance frequency f1 of the fundamental mode of the loop-shaped radiation electrode 3 can be variably controlled, so that the resonance frequency f1 of the fundamental mode can be easily set to the set frequency.

In the example shown in FIG. 10, the base 2 is made of a dielectric, and the ground electrode 30 and the fixing electrode 31 as shown in the fifth embodiment are formed on the base 2. At the same time, holes 36 and 37 are formed. As described above, by forming the holes 36 and 37 in the base 2, the effective dielectric constant of the base 2 is reduced, and the antenna characteristics can be improved.

The present invention is not limited to the above embodiments, but may take various embodiments. For example, the base 2 of the antenna 1 may be constituted by a laminate as shown in FIGS. Note that FIG.
FIG. 12B is a diagram showing the base 2 shown in FIG. 11A in an exploded state. Further, in the example shown in FIG.
Although the laminated body of the sheet portions 40 and 41 has been described, the base 2 may be configured by laminating and integrating two or more sheet portions.

In each of the above embodiments, the loop-shaped radiation electrode 3 is formed on the surface of the base 2 over the entire length. However, in the case where the base 2 is formed of a laminate as described above, For example, as shown in FIGS. 11A and 11B, a configuration in which a part of the loop-shaped radiation electrode 3 is formed inside the base 2 may be adopted. Further, the loop-shaped radiation electrode 3 may be formed inside the base 2 over the entire length. Thus, a part or all of the loop-shaped radiation electrode 3 is
In the above embodiments, the loop-shaped radiating electrode 3 may be formed in such a manner that the open end 3a of the looped radiating electrode 3 is opposed to the power supply end side electrode portion with an interval therebetween to form a capacitor. The same effect as the example can be obtained.

Further, in addition to the configuration shown in each of the above embodiments, as shown in FIG. 12, a projecting radiation electrode portion 44 is formed from the feeding end side electrode portion of the loop radiation electrode 3 toward the open end 3a. It may be formed. The protruding radiation electrode portion 44 is configured to be capable of resonating in response to a signal supplied from the power supply electrode 4, and the extended distal end of the protruding radiation electrode portion 44 faces the open end 3 a with an interval therebetween. To produce the capacity.

As described above, by providing the projection radiation electrode portion 44 at the power supply end side electrode portion of the loop radiation electrode 3, the loop radiation electrode 3 can be seen when the projection radiation electrode portion 44 is not provided. It has a resonance mode that did not exist, and it is possible to provide more frequency bands.
In addition, similarly to the above-described embodiments, the capacitance between the open end 3a of the loop-shaped radiation electrode 3 and the projection radiation electrode portion 44 can be varied to reduce the fundamental mode resonance frequency f1 of the loop-shaped radiation electrode 3. Since the interval between the resonance frequency f1 and the higher-order mode resonance frequency f2 can be changed without largely changing, the variable control of the resonance frequency f2 is facilitated.

Further, in each of the above embodiments, the open end 3a of the loop-shaped radiation electrode 3 is disposed on the upper surface 2a of the base 2. For example, the position of the open end 3a is determined by the upper surface 2a of the base 2. However, the present invention is not limited to this, and may be disposed on, for example, the side surface or the bottom surface of the base 2 in accordance with the arrangement position of the power supply electrode 4 or the route of the loop of the loop-shaped radiation electrode 3.

Further, FIG. 1, FIG. 4, FIG. 6, FIG. 8, FIG.
In the example shown in FIG. 10, the protruding electrode portion 18 facing the open end 3 a with a space therebetween is formed at the power supply end side electrode portion of the loop-shaped radiation electrode 3. However, the protruding electrode portion 18 is not necessarily formed. Not something you have to do,
The overhanging electrode section 18 may not be provided.

Further, in each of the above embodiments, the base 2 is a rectangular parallelepiped. However, for example, the base 2 may be a column other than a rectangular parallelepiped.

Further, FIG. 6 shown in the fourth embodiment example
Alternatively, the configuration of the plurality of radiation electrodes including the loop-shaped radiation electrode of FIG. 7 and the configuration of the plurality of radiation electrodes including the loop-shaped radiation electrode illustrated in FIG. 8 may be combined. Further, in each of the examples of FIGS. 6 to 8 shown in the fourth embodiment, one radiation electrode different from the loop-shaped radiation electrode 3 is provided on the base 2. A plurality of radiation electrodes different from the above may be provided. For example, FIG.
(A) and (b) respectively. FIG. 13 (a)
In the example shown in FIG. 3, radiation electrodes 22 and 44 different from the loop radiation electrode 3 are formed, and these radiation electrodes 22 and 4 are formed.
Numeral 4 is connected to the common feeding electrode 4 together with the loop-shaped radiation electrode 3.

In the example shown in FIG. 13B, the radiation electrodes 22 and 44 different from the loop-shaped radiation electrode 3 are formed as in the example shown in FIG. Unlike the example shown in FIG. 13A, the reference numerals 22 and 44 are not connected to the power supply electrode 4.
Sub-feeding wiring pattern 26 formed on circuit board 15
Via (26a, 26b), it is communicatively connected to the power supply wiring pattern 25 of the circuit board 15. Of course, three or more radiation electrodes different from the loop radiation electrode 3 may be formed. Reference numeral 45 in FIG. 13B indicates a matching chip coil component.

Further, in each of the above embodiments, only one loop-shaped radiation electrode 3 is provided. However, as shown in FIG.
It is good also as a structure provided with at least one sub loop radiation electrode 3 '. Thus, when the main loop-shaped radiation electrode 3 and the sub-loop-shaped radiation electrode 3 'are provided,
The power supply end of each of the loop-shaped radiation electrodes 3 and 3 ′ may be commonly connected to the power supply electrode 4, or the power supply wiring pattern 25 and the sub power supply as shown in FIG. The wiring pattern 26 is formed, and the main loop-shaped radiation electrode 3 is connected to the power supply wiring pattern 25 via the power supply electrode 4, and the sub loop-shaped radiation electrode 3 ′ is connected via the sub power supply wiring pattern 26. It may be configured to be connected to the power supply wiring pattern 25.

As described above, by disposing a plurality of loop-shaped radiation electrodes, it is possible to use both the fundamental mode and the higher-order mode of each loop-shaped radiation electrode, and to transmit radio waves in more frequency bands. Transmission or reception becomes possible.

Further, in the second embodiment, the meandering electrode portion 20 is interposed in the large current distribution region A of the loop-shaped radiation electrode 3. For example, as an application example thereof, the loop-shaped radiation electrode 3 may be provided with an inductor electrode portion configured to locally narrow a part of the large current distribution side region A to provide an inductance to the large current distribution side region A.

Further, in the fifth embodiment, the ground electrodes 30 are provided at three places, but the number of the ground electrodes 30 is not limited to the number.

Further, in the sixth embodiment, a configuration is adopted in which an inductance is imparted to the power supply wiring pattern 25 by using a chip coil component. For example, instead of the chip coil component, a meander A configuration may be used in which an inductance is given to the power supply wiring pattern 25 using a pattern (inductor portion). Further, a configuration may be adopted in which an inductance is given to the power supply wiring pattern 25 by combining a chip coil component and a meander pattern.

Further, in the sixth embodiment, the inductor portion for providing the inductance is provided to the power supply wiring pattern 25. For example, when the sub power supply wiring pattern 26 is formed, The power supply wiring pattern 26 may be provided with an inductor portion similar to the above.

[0104]

According to the present invention, since the antenna is mounted on the non-ground area of the mounting board, the radiating electrode of the antenna is disposed at a distance from the ground of the mounting board. The capacitance between the ground and the ground is reduced, so that the frequency band can be widened without increasing the size of the base, and it is easy to improve both the widening of the frequency band and the miniaturization of the antenna.

Further, according to the present invention, since the open end of the radiating electrode is formed as a loop-shaped radiating electrode opposed to the power supply end side electrode portion with a space therebetween, the open end and the power supply end side A capacitance is generated between the electrode portions, and by varying the capacitance, the resonance frequency of the fundamental mode of the loop-shaped radiation electrode is not largely changed, and the resonance frequency of the fundamental mode and the resonance frequency of the higher-order mode are not changed. The interval can easily be variably controlled. That is, the variable control of the resonance frequency of the higher-order mode can be performed almost independently of the fundamental mode. This makes it easy to design the resonance frequencies of the fundamental mode and the higher-order mode to be the required frequencies, respectively. Therefore, both the fundamental mode and the higher-order mode of the loop-shaped radiation electrode are used. Transmission or reception of radio waves becomes possible.

As a result, it is possible to cope with multi-banding simply by providing one loop-shaped radiating electrode, and in combination with the above-described effects, the frequency band can be widened, the antenna can be downsized, and the multi-banding can be realized. Can be provided.

Also, in the present invention, a communication device having a surface-mounted antenna structure having a unique configuration has a wide frequency band, is small, and has a plurality of frequency bands. Can be.

In the case where a meander electrode portion for providing an inductance is provided on the large current distribution region of the loop-shaped radiation electrode, the meander electrode portion provides an inductance in the large current distribution region of the loop-shaped radiation electrode. Is given, the electric length of the large current distribution side region is lengthened, whereby the resonance frequency of the loop-shaped radiation electrode can be reduced without increasing the size of the antenna base. Therefore, the size of the antenna can be further reduced.

In the invention in which the loop-shaped radiation electrode is formed with a loop path returning from the top surface of the base to the side surface, the mounting bottom surface, and the side surface to return to the top surface, the object that can be regarded as ground is, for example, the mounting substrate. Even if the antenna moves relatively far and near to the antenna in a direction orthogonal to the antenna mounting surface, the loop-shaped radiation electrode can perform the antenna operation stably without being substantially affected by the movement of the object. . Thus, a change in antenna characteristics due to the movement of the object can be substantially suppressed. Thereby, the reliability of the antenna characteristics can be improved.

A plurality of radiating electrodes including a loop-shaped radiating electrode are provided by connecting their respective power supply ends to a common power supply electrode, and a power supply wiring pattern and a sub power supply wiring pattern are provided on a mounting substrate. Are formed on the base of the antenna, and a radiation electrode connected to the wiring pattern for power supply and a radiation electrode connected to the wiring pattern for sub-power supply are formed in a loop shape. Since a plurality of radiating electrodes including the radiating electrode are formed, transmission or reception of a radio wave in a wider frequency band becomes possible.
It is possible to cope with one or more applications, and it is possible to further promote multiband.

A ground electrode is provided, and the ground electrode has a structure capable of providing a capacitance between the region of the loop-shaped radiation electrode where the higher-order mode electric field is strongest and the ground. By varying the capacitance between the high-order mode electric field strongest region of the loop-shaped radiation electrode and the ground, the resonance frequency of the higher-order mode is variably controlled without substantially changing the resonance frequency of the fundamental mode. It is possible. For this reason, the variable control of the capacitance between the electric field strongest region of the higher order mode and the ground in the loop-shaped radiation electrode, and the capacitance between the open end of the loop-shaped radiation electrode and the power supply end side electrode portion as described above. By using both the variable control of the first mode and the variable control of the higher mode, the variable control of the resonance frequency of the higher-order mode becomes easier, and the respective resonance frequencies of the fundamental mode and the higher-order mode can be set to the required frequencies with high accuracy. It becomes possible. This allows
The reliability of the antenna characteristics can be further improved.

In the case where the electrode dedicated to solder fixing is formed on the base, the base of the antenna can be firmly fixed to the mounting substrate, and the reliability of durability can be improved.

In the case where the inductor portion for providing inductance to the power supply wiring pattern of the mounting board is provided, the size of the base is increased and the path length of the radiation electrode connected to the power supply wiring pattern is reduced. By giving inductance to the power supply wiring pattern without increasing the length, it is possible to reduce the fundamental mode resonance frequency of the radiation electrode connected to the power supply wiring pattern. For this reason, the size of the antenna can be further reduced.

In the case where the plurality of radiating electrodes including the loop-shaped radiating electrodes are arranged on different base forming surfaces, the base is enlarged and the interval between the radiating electrodes is increased. Since the mutual interference between the radiation electrodes can be suppressed without expanding the size of the antenna, the size of the antenna can be reduced.

In a communication device in which an antenna is provided in a corner region of a circuit board of the communication device so as to satisfy a condition that a current flowing through a radiation electrode and a current flowing through a ground region of the circuit board are strengthened, The current flowing through the ground region is large and contributes to the directivity of the antenna, so that the antenna can have strong directivity. For this reason, for example, it is possible to suppress a change in antenna characteristics when an object that can be regarded as ground relatively moves toward and away from the antenna, thereby improving the reliability of the antenna characteristics.

[Brief description of the drawings]

FIG. 1 is a model diagram schematically showing a characteristic surface mount antenna structure in a first embodiment.

FIG. 2 is an explanatory diagram schematically showing a mounting example of a characteristic antenna according to the first embodiment.

FIG. 3 is a graph showing a change in frequency characteristics of the loop-shaped radiation electrode due to a change in capacitance between an open end of the loop-shaped radiation electrode and a power supply end side electrode portion.

FIG. 4 is a model diagram schematically showing a characteristic antenna extracted in the second embodiment.

FIG. 5 is a model diagram schematically showing a characteristic surface mount antenna structure in the third embodiment.

FIG. 6 is a model diagram schematically showing an example of a characteristic antenna configuration in the fourth embodiment.

FIG. 7 is a model diagram schematically showing another configuration example of a characteristic antenna in the fourth embodiment.

FIG. 8 is a model diagram schematically showing another configuration example of a characteristic antenna according to the fourth embodiment.

FIG. 9 is an explanatory view schematically showing a characteristic surface mount antenna structure in the fifth embodiment.

FIG. 10 is an explanatory diagram schematically showing a characteristic surface mount antenna structure in the sixth embodiment.

FIG. 11 is a diagram for explaining another embodiment of the base and another embodiment of the loop-shaped radiation electrode.

FIG. 12 is a model diagram showing still another embodiment of the loop-shaped radiation electrode.

FIG. 13 is a model diagram showing an example of a case where a plurality of radiation electrodes different from the loop radiation electrodes are provided.

FIG. 14 is a model diagram showing an example of a case where a plurality of loop-shaped radiation electrodes are provided.

FIG. 15 is an explanatory view showing a conventional example of a surface mount antenna.

FIG. 16 is an explanatory view showing a conventional example of a surface mount antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Substrate 3 Loop radiation electrode 4 Feed electrode 15 Circuit board 16 Non-ground area 17 Ground electrode 20 Meander-shaped electrode part 22, 44 Radiation electrode 25 Feeding wiring pattern 26 Sub feeding wiring pattern 30 Ground electrode 31 Fixing electrode 34,35 Chip coil parts

Claims (10)

[Claims] An antenna having a radiation electrode formed on a base and a power supply electrode for supplying a signal to one end of the radiation electrode is mounted on a mounting substrate and supplied from the power supply electrode. A fundamental mode antenna operation and a higher order mode antenna operation of the radiation electrode can be performed according to a signal, and a surface mount antenna structure having a plurality of frequency bands different from each other. The power supply electrode is connected to the power supply electrode, and the other end is an open end. The radiation electrode is provided between the open end and the power supply end side electrode portion to control a resonance frequency of a higher-order mode. The outer loop-shaped radiating electrode with the capacitance of
Also, a non-ground area is formed on the mounting board, and the antenna is mounted on the non-ground area of the mounting board. 2. The surface-mounted antenna structure according to claim 1, wherein the loop-shaped radiation electrode is provided with a meander electrode portion for providing an inductance to a large current distribution region. 3. The power supply electrode is formed on the side surface of the base, and the loop-shaped radiation electrode is formed on the upper surface of the base from the power supply electrode. 3. The surface mounting device according to claim 1, wherein the surface mounting device is formed with a return loop path, and is arranged so as to form a capacitor between the open end and the power supply end side electrode portion. Type antenna structure. 4. The antenna according to claim 1, wherein a plurality of radiation electrodes including a loop-shaped radiation electrode are provided on the base of the antenna such that each of the power supply ends is connected to a common power supply electrode. The surface-mounted antenna structure according to claim 2 or 3. 5. A power supply wiring pattern connected to a power supply electrode of an antenna is formed on a mounting board, and a sub power supply wiring pattern having an inductance component for adjusting a resonance frequency is branched from the power supply wiring pattern. A radiation electrode is formed on the base of the antenna so as to be connected to the power supply wiring pattern via a power supply electrode, and is connected to the sub power supply wiring pattern. 5. The surface-mounted antenna structure according to claim 1, wherein another radiation electrode is formed. 6. The antenna according to claim 1, wherein a ground electrode is provided on the base of the antenna for providing a capacitance between the high-order mode electric field strongest region of the loop-shaped radiation electrode and the ground. A surface-mounted antenna structure according to any one of claims 1 to 5. 7. The antenna according to claim 1, wherein the antenna is configured to be mounted on a mounting board by solder, and an electrode dedicated to solder fixing for bonding the solder to the base is formed on the base. The surface-mounted antenna structure according to any one of claims 1 to 6. 8. The power supply wiring pattern connected to the power supply electrode of the antenna is formed on the mounting board, and the power supply wiring pattern is provided with an inductor portion for providing an inductance. The surface-mounted antenna structure according to any one of claims 1 to 7. 9. A base of the antenna is formed in a rectangular parallelepiped shape, and a plurality of radiating electrodes including a loop-shaped radiating electrode are formed on a surface of the base. The surface-mounted antenna structure according to any one of claims 1 to 8, wherein the surface-mounted antenna structure is provided on a different surface. 10. A surface-mounted antenna structure according to claim 1, wherein a mounting board of the surface-mounted antenna structure is constituted by a circuit board of a communication device. A communication device characterized in that a current flowing through a radiation electrode and a current flowing through a ground region of a circuit board are arranged in a corner area of the circuit board so as to satisfy a condition having directivity.