JP2009225199A - Antenna structure for compact radio apparatus, forming method thereof and radio identification tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna structure which is small in size and effectively transmits a measurement result without being affected by a radiowave absorber. <P>SOLUTION: In an antenna portion 10 connected to a tag 10, a metallic reflection plate 22 is provided on the back of dielectrics 24, a linear antenna 26 of Peano curve or the like is formed on a front side, a power feeding terminal 30 is provided in an end portion of the linear antenna 26 and further, ground terminals 40, 40 are provided at a predetermined interval on both sides of the power feeding terminal 30. Thus, radiation characteristics can be obtained that, even with thickness where the antenna element 26 and the reflection plate 22 are proximate, capacity is maintained between the ground terminal 40, 40 and the power feeding terminal 30, impedance matching with a circuit side is achieved at an effective resonant frequency, and no influence is exerted from a radiowave absorber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna structure, an antenna formation method, and a wireless identification tag in a small wireless device, and more particularly, for example, an antenna in a small wireless device suitable for use in a measurement system that measures and transmits biological information such as body temperature and heartbeat. The present invention relates to a structure, an antenna forming method thereof, and a wireless identification tag.

  For example, in a medical site such as a hospital, body area networks that measure biological information such as body temperature or heartbeat and collect the results cordlessly by a wireless device such as a portable terminal have attracted attention. On the other hand, RFID (wireless identification) tags that are affixed to, attached to, or built into various properties and are used for identifying the objects by radio signals are in practical use. Therefore, it is conceivable to construct a body area network with a smaller wireless device by combining a wireless identification tag and a sensor for measuring biological information.

  Conventionally, what was described in patent document 1 or patent document 2 etc. as the above radio | wireless identification tags is proposed. For example, a wireless identification tag described in Patent Document 1 includes at least a dielectric member, an antenna pattern for transmission / reception that forms a loop antenna provided on the surface of the dielectric member, a communication circuit, and a storage circuit. And a connected IC chip electrically connected to the pattern. In particular, the antenna structure has a configuration in which a loop antenna is patterned on the surface of a film-like dielectric, and feed lines are provided on both sides of the loop antenna. The antenna pattern thus formed is wound around, for example, a box-shaped mounting pad, and the antenna power supply line at the end of the film is connected from both sides of the IC chip mounted on one side thereof to form a tag. It was. That is, the antenna extends on both sides of the tag.

  In such a configuration, one side of the tag is affixed to a predetermined part such as a radio wave absorber such as a human body with a double-sided tape or the like, and exchanges signals with the main device (reader / writer). At that time, since the antenna extends on both sides, a large current loop is formed on both sides of the tag so that it is not affected by a radio wave absorber such as a human body, that is, it has an effect of suppressing a decrease in communication distance. It was. In addition to the box-shaped pad, the pad may be various ones such as a cylinder, a triangular prism, or a sphere, and the film-shaped loop antenna is wound around the pad.

The wireless identification tag described in Patent Document 2 has a UHF band antenna formed in a flat plate shape so that the surface of the dielectric substrate is covered with metal, and a surface of the antenna so that the antenna is accommodated at the end. A coiled 13 MH band loop antenna was formed so that good radiation reception characteristics of radio waves of both frequencies could be obtained even when used near the human body.
JP 2006-53833 A JP 2006-128953 A

  However, the above-described conventional technique has a problem that the efficiency is deteriorated because the radio wave is radiated to the radio wave absorber side such as a human body. Therefore, it is conceivable to provide directivity by providing a reflector on the surface facing the human body. However, in a half-wave antenna, when it is desired to set the directivity in one direction by providing a reflector, it is necessary to attach the reflector behind the antenna with a distance of a quarter wavelength of the resonance frequency. Further, when the antenna and the reflector are arranged close to each other, there is a problem that the input impedance becomes extremely small and it is difficult to match the impedance of a practical circuit. Further, it is known that the input impedance is smaller than the metal resistance and the radiation efficiency is lowered.

  The present invention has been made in view of the above circumstances, and even when a reflector is provided on an antenna to provide directivity, the antenna can be thinned without lowering the radiation efficiency, and can be easily matched with a circuit. An object of the present invention is to provide an antenna structure and a method for forming the antenna structure in a small wireless device that can be achieved, and a wireless identification tag.

  In order to achieve the above object, the present invention provides an antenna structure in a small wireless device that is mounted at a desired location and transmits a predetermined signal, and includes a dielectric (24) formed in a flat plate shape, A linear antenna element (26) provided on the surface of the body, a power supply terminal (30) provided at an end of the antenna element and connected to a small wireless device, and a power supply terminal provided in the vicinity of the power supply terminal And a ground plate (40, 40) formed with a gap therebetween and a reflection plate (22) provided on the back surface of the flat dielectric to reflect electromagnetic waves from the antenna element. It consists of an antenna structure in the device.

  In this case, the power supply terminal (30) is a waveguide 301 in which ground terminals (40, 40) having a conductive foil pattern formed on the surface of the dielectric 24 are provided on both sides with a gap therebetween, and the antenna element 26 is provided. In addition, a conductor foil may be patterned on the surface of the dielectric 24, and the waveguide 301 may be formed together with the ground terminals (40, 40) to form the coplanar line 30A.

  In the antenna structure, the power supply terminal 30 may be formed by a microstrip line (60) that connects the antenna element 26 and the small wireless device (10).

  In the antenna structure, the antenna element may be a half-wave dipole antenna.

  Further, in the antenna structure, it is advantageous that the antenna element is a Peano curve-shaped antenna (26) which is bent a plurality of times to fill a part of the surface of the dielectric.

  In the antenna structure, the antenna element may be a meander-curved antenna (100) formed by bending a plurality of antenna elements into a rectangular shape.

  In the antenna structure, it is advantageous that the small wireless device is a wireless identification tag that transmits an identification code of the own device to the main device.

  Further, the wireless identification tag of the present invention is a wireless identification tag for transmitting an identification signal of its own device to the main device, a signal generating means for generating the identification signal, and a signal including the identification signal from the signal generating means as the main device. Transmitting and receiving means for transmitting and receiving, and an antenna part connected to the transmitting and receiving means, the antenna part comprising a flat dielectric, a linear antenna element formed on the surface of the dielectric, and an antenna element It includes a power supply terminal formed at the end, a ground terminal formed at a predetermined interval on both sides of the power supply terminal, and a metal reflector formed on the back surface of the dielectric.

  In the wireless identification tag of the present invention, the power feeding terminal (30) of the antenna portion is a conductive terminal having a grounding terminal (40, 40) in which a conductive foil is patterned on the surface of the dielectric 24, with a gap provided on both sides. The waveguide 301 may be constituted by a waveguide 301 that is patterned with a conductive foil on the surface of the dielectric 24 together with the antenna element 26 and forms the coplanar line 30A together with the ground terminals (40, 40).

  In the wireless identification tag of the present invention, the feeding terminal of the antenna part may be formed by a microstrip line that connects between the antenna element and the transmitting / receiving means.

  Furthermore, in the wireless identification tag of the present invention, the antenna element of the antenna part may be a half-wave dipole antenna.

  In addition, the above-described wireless identification tag is advantageously a Peano-curved antenna in which the antenna element at the antenna portion is bent a plurality of times to fill a part of the surface of the dielectric.

  Furthermore, the radio identification tag of the present invention may be a meander-curved antenna formed by bending a plurality of antenna elements at the antenna portion into a rectangular shape.

  Further, the present invention provides a method for forming an antenna portion in a small wireless device that is mounted at a desired location and transmits a predetermined signal, and a linear antenna element is formed on a surface of a dielectric formed in a flat plate shape. And a step of providing a metal reflector on the back surface of the dielectric, and in the step of forming the antenna element, a feed terminal connected to the small wireless device is provided at the end of the antenna element, and A method for forming an antenna part, characterized in that a grounding terminal is provided in the vicinity of a feeding terminal of a linear antenna with a predetermined gap from the feeding terminal, and a desired resonance frequency of the antenna element is obtained by adjusting the spacing Consists of

  According to the method for forming an antenna portion of the present invention, a feeding terminal is formed by a coplanar line-shaped waveguide formed by patterning a conductor foil on the surface of a dielectric together with an antenna element, and similarly, a ground terminal is formed on the surface of the dielectric. The conductive foil may be formed by a coplanar line-shaped portion on which a pattern is formed.

  At that time, as a method of forming the antenna part, the power feeding terminal may be connected between the antenna element and the small wireless device by a microstrip line.

  In the method for forming an antenna portion of the present invention, the antenna element may be formed by a half-wave dipole antenna.

  In the method for forming an antenna portion of the present invention, it is advantageous that the antenna element is formed by a Peano curve antenna that is bent a plurality of times to fill a part of the surface of the dielectric.

  Furthermore, in the method for forming an antenna portion according to the present invention, the antenna element may be formed by a meander-curved antenna formed by bending a plurality of antenna elements into a rectangular shape.

  In the antenna part forming method of the present invention, the small wireless device may be a wireless identification tag that transmits an identification code of the own device to the main device.

  According to the antenna structure in the small wireless device of the present invention, the antenna structure in the small wireless device is mounted at a desired location and transmits a predetermined signal, and is formed of a flat plate-shaped dielectric and a surface of the dielectric A linear antenna element provided at the end of the antenna element, a power supply terminal provided at an end of the antenna element and connected to a small wireless device, and a ground provided in the vicinity of the power supply terminal with a predetermined gap Since it is configured to include a terminal and a reflector provided on the back surface of the flat dielectric to reflect electromagnetic waves from the antenna element, the impedance is appropriately adjusted by the capacitance between the feeding terminal and the ground terminal at the antenna end. An antenna and a small wireless device which are held and have a thin and high radiation efficiency can be configured.

  The feeding terminal is a coplanar waveguide having a conductive foil pattern formed on the surface of the dielectric together with the antenna element. Similarly, the ground terminal is a coplanar having the conductive foil patterned on the surface of the dielectric. Since it is a line-shaped part, the antenna element and the ground terminal can be easily formed on the surface of the dielectric.

  In addition, since the feeding terminal is formed by a microstrip line that connects the antenna element and the small wireless device, it is advantageous when the connection between the small wireless device is corrected later.

  Further, since the antenna element is a half-wave dipole antenna, the element can be easily formed.

  Further, since the antenna element is a Peano curve antenna that is bent a plurality of times and fills a part of the surface of the dielectric, the element can be easily formed.

  Further, since the antenna element is a meander curve antenna formed by bending a plurality of rectangles, the antenna element can be easily formed as compared with the Peano curve, and the radiation efficiency can be increased as compared with the dipole antenna. .

  Further, since the small wireless device is a wireless identification tag that transmits the identification code of the own device to the main device, a further small device can be configured by the antenna structure.

  According to the wireless identification tag of the present invention, the signal generation means for generating the identification signal, the transmission / reception means for transmitting / receiving a signal including the identification signal from the signal generation means to / from the main device, and the transmission / reception means are connected. The antenna part includes a planar dielectric, a linear antenna element formed on the surface of the dielectric, a feed terminal formed at the end of the antenna element, and both sides of the feed terminal Including a grounding terminal formed at a predetermined interval and a metal reflector formed on the back surface of the dielectric, it is effective even when attached to a radio wave absorber such as a human body. Communication can be performed.

  Further, according to the above wireless identification tag, the feeding terminal of the antenna portion is a coplanar line-shaped waveguide in which a conductor foil is patterned on the surface of the dielectric together with the antenna element. Similarly, the ground terminal is a dielectric terminal. Since it is a coplanar line-shaped portion in which conductor foil is patterned on the surface of the body, the antenna element and the ground terminal can be easily formed on the surface of the dielectric.

  Further, according to the above-described wireless identification tag, the feeding terminal of the antenna part is formed by the microstrip line that connects the antenna element and the transmitting / receiving means, which is advantageous when the connection is corrected later. It is.

  Also, according to the above-described wireless identification tag, the antenna element at the antenna portion is a half-wave dipole antenna, so that the antenna can be easily formed.

  Also, according to the above-described wireless identification tag, the antenna element at the antenna portion is a Peano curve antenna that is bent a plurality of times and fills a part of the surface of the dielectric, so that efficient communication can be performed. Can do.

  Further, according to the above-described wireless identification tag, the antenna element at the antenna portion is a meander-curved antenna formed by bending a plurality of rectangles, so that the configuration is simpler than the Peano curve and more efficient than the dipole antenna. Good communication.

  Further, according to the above-mentioned wireless identification tag, since it is a passive tag including electromagnetic induction means activated by electromagnetic field energy from the main device, a more compact device can be configured without incorporating a battery. .

  In addition, according to the above-described wireless identification tag, the sensor includes a sensor that measures a predetermined measurement target, and the result of the sensor is transmitted to the main apparatus together with the identification signal. Therefore, the wireless identification tag can be applied to measurement of biological information.

  In addition, according to the method for forming an antenna part of the present invention, in the method for forming an antenna part in a small wireless device that is attached to a desired part and transmits a predetermined signal, the surface of the dielectric formed in a flat plate shape A step of forming a linear antenna element and a step of providing a metal reflector on the back surface of the dielectric, and in the step of forming the antenna element, the end of the antenna element is connected to the small wireless device. A power supply terminal to be connected is provided, and further, a ground terminal is provided in the vicinity of the power supply terminal of the linear antenna with a predetermined gap from the power supply terminal, and the interval is adjusted to obtain a desired resonance frequency of the antenna element. Therefore, even when the metal plate is provided close to the back surface of the antenna, a desired input impedance can be obtained and matching with the circuit can be ensured.

  In addition, according to the above method for forming an antenna part, the feeding terminal forms a coplanar line-shaped waveguide by patterning a conductor foil on the surface of the dielectric together with the antenna element, and similarly, the ground terminal is a dielectric Since the conductor foil pattern is formed on the surface of the body to form a coplanar line-shaped portion, the antenna element and the ground terminal can be easily formed on the surface of the dielectric.

  Further, according to the above method for forming an antenna portion, the feeding terminal connects the antenna element and the small wireless device by the microstrip line, which is advantageous when the connection is corrected later.

  Further, according to the above-described method for forming an antenna portion, the antenna element is formed by a half-wave dipole antenna, so that the element can be easily formed.

  In addition, according to the above method for forming an antenna portion, the antenna element is formed by a Peano curve antenna that is bent a plurality of times and fills a part of the surface of the dielectric, so that the element can be easily formed. Can be done.

  In addition, according to the method for forming an antenna part, the antenna element is formed by a meander-curved antenna formed by bending a plurality of rectangles into a rectangular shape, so that it can be formed more easily than a Peano curve. The radiation efficiency can be increased compared to a dipole antenna.

  Further, according to the above-described method for forming the antenna part, the small wireless device is a wireless identification tag that transmits the identification code of the own device to the main device, so that a smaller device can be configured.

  Next, an antenna structure and a method for forming the antenna structure and a wireless identification tag according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a wireless identification tag to which an antenna structure according to the present invention is applied. In the wireless identification tag according to the present embodiment, an antenna 20 unique to the present application is connected to a tag body 10 including a sensor for measuring body temperature and the like by a coplanar line 30A. In particular, the main feature of the present embodiment is that the reflector 22 is formed on the back surface of the antenna 20 and the ground terminals 40 are formed on both sides of the feeding terminal 30 at the end of the antenna element. is there.

  The details of each of the above-described parts will be described. The tag body 10 includes at least a transmission / reception circuit and an identification code generation circuit. In this embodiment, the tag body 10 includes a battery and a sensor that measures biological information. A coplanar line 30 </ b> A connected to the power feeding terminal 30 of the antenna is formed on the surface of the main body. The power supply terminal 30 includes a waveguide 301 that forms a coplanar line 30 </ b> A together with ground terminals 40, 40 arranged with a gap on both sides. That is, the power supply terminal 30 is connected to a battery (not shown) on the tag body side, with the antenna element 26 and a conductor foil linearly formed on the surface of the dielectric 24. The ground terminals 40, 40 are arranged with gaps on both sides of the linear power supply terminal. The ground terminal is configured by patterning a conductor foil on the surface of the dielectric 24.

  The antenna 20 includes a reflection plate 22, a dielectric 24, an antenna element 26, a power supply terminal 30, a ground terminal 40, and a support base 42. The reflection plate 22 is a shielding plate such as copper or gold, and is formed on the entire back surface of the dielectric 24. The dielectric 24 is made of polyimide having a dielectric constant ε = 3.5, and has a thickness of about 50 μm in this embodiment.

すなわち、ＬｘとＬｙは次式（４）、（５）で表される。

In this embodiment, the antenna element 26 is formed by patterning a metal linear element made of an alloy of copper and gold on the surface of the dielectric 24. In particular, in this embodiment, as shown in FIG. It is formed in a Peano curve. As shown in FIGS. 4 and 5, the Peano curve is formed by, for example, a curve in which each side of a square is equally divided into rn pieces and all small eyes formed therein are connected with one stroke. In particular, when r = 2, it is called a Hilbert curve, and when r = 3, it is called a Peano curve, and n is a repeat order. In the case of r = 3 Peano curve, when n = 1, it is the same shape as the meander curve often used as the shape of the folded line antenna. FIG. 5 shows the case of a meander curve with n = 1, and FIG. 6 shows the case of a Peano curve with n = 2. In these figures, it is known that dx = dy = d. In this case, the relationship between the line length S and d of the curve is expressed by the following equations (1), (2), (3). It is represented by

That is, Lx and Ly are expressed by the following equations (4) and (5).

  Returning to FIG. 2, the end of the Peano-curved antenna element 26 formed as in the above equation is extended to the tag body 10 side and formed as a power supply terminal 30. On both sides of the power supply terminal 30, ground terminals 40, 40 formed in a coplanar line shape with a predetermined gap are formed. In this case, the ground terminals 40, 40 are respectively shown as having a horizontal width Lwx and a vertical width Lgy, and their relationship is shown in FIGS. FIG. 7 shows a case where the horizontal width Lwx is changed while the vertical width Lgy is kept constant, and FIG. 8 is an enlarged view thereof, and a higher impedance can be obtained when the horizontal width Lwx is shorter. FIG. 9 shows a case where the horizontal width Lwx is constant and the vertical width Lgy is changed, and FIG. 10 is an enlarged view thereof. From these figures, the smaller the area of the ground terminals 40, 40, the more capacitive and high impedance can be obtained. In this way, the area of the ground terminals 40, 40 is changed to form a desired resonance frequency and input impedance. As shown in FIG. 6, the power supply terminal 30 and the ground terminals 40 and 40 are connected to corresponding portions on the tag body 10 side formed in a coplanar line shape.

  In the configuration as described above, the tag of the present embodiment is attached to a predetermined part of the human body X with the double-sided tape 50 or the like, and transmits the biological information constantly measured by the sensor to the main device (not shown) together with the identification code.

  As described above, according to the wireless identification tag according to the present embodiment, the antenna 20 includes the flat dielectric 24, the linear antenna element 26 formed on the surface of the dielectric, and the end of the antenna element 26. Power supply terminal 30, ground terminals 40 and 40 formed at predetermined intervals on both sides of power supply terminal 30, and metal reflector 22 formed on the back surface of dielectric 24, Even if it is thin and attached to a radio wave absorber such as a human body, it is not affected by this, and effective communication can be performed.

  That is, when power is supplied to the center of the antenna as in the prior art, the back reflector has to be arranged at a distance of a quarter wavelength of the resonance frequency from the antenna element. Since the antenna is fixedly formed in a flat shape and the feeding point by the feeding terminal 30 is formed at the end of the antenna element 26, the distance between the antenna element 26 and the reflector 22 can be effectively shortened. FIG. 11 and FIGS. 12 to 13 show the principle and the result of the simulation. That is, when the distance between the antenna element and the reflector is h, the length of the antenna element is L, and the distance from the center of the feeding point of the antenna element is dx, the central feeding and dx = 0 mm, h = 0.25λ, In the case of a 1/4 wavelength distance, the impedance was approximately 70 + j0Ω as shown in FIGS. However, FIG. 12 represents a real part and FIG. 13 represents an imaginary part. Further, when dx = 0 and the reflector is brought close to the antenna element, for example, h = 0.01λ, the impedance is almost zero at the series resonance frequency near 1 GHz, and at the parallel resonance frequency of 2 GHz, It cannot be used as an antenna because of the change. Therefore, when dx = −70 mm in the state of h = 0.001λ, that is, when the feeding point is moved to the end of the antenna element, as shown in FIG. 12, the input impedance becomes several tens of Ω near the resonance frequency near 1 GHz, A practical input impedance applied to this embodiment is obtained.

  Next, according to the wireless identification tag according to the present embodiment, the area of the ground terminals 40 and 40 can be changed with respect to the antenna feeding terminal 30 to achieve matching with the circuit as an effective capacity. That is, as described above, as shown in FIGS. 7 to 10, when the area of the ground terminal, that is, the ground electrode (40, 40) is reduced, the input impedance becomes more capacitive. Thus, even when the back reflector 22 is sufficiently close to the wavelength of the antenna element 26, power can be supplied to the end of the linear element, and practical input impedance can be obtained while matching with the circuit. Can do.

ただし、図５、図６におけるユニットをＮ個組み合わせることと給電部への接続を考えて、通常知られるペアノ曲線の全長にｄｙを付け加えている。さらに、本アンテナの場合、ＮＳｎ＝ｍλ／２を満たす必要があり、１８０度の位相差を隣り合う線路上の電流に与えることは通常難しい。ここでＮは自然数が基本であるが、共振周波数と求められるアンテナ素子の大きさを考えて、そうでない場合もある。たとえば、Ｎは１〜１０程度の値であるがｄｘ、ｄｙの関係で決まる。また、ｍは自然数であり、小型アンテナということを考えるとｍ＝１とすべきである。図１４は、図２のペアノ曲線の場合と同様に、ｎ＝２，Ｎ＝６に対し、ｄｘ／ｄｙ＝１．１２５とした場合のメアンダ曲線の例である。これらを比較すると、図１５に示すように、Ｓ１１特性は、４３３ＭＨｚである。この場合、Ｌｘ＝０．００５λ程度であるが、この周波数のゲイン特性は、図１６に示すようにほとんど差が見られない。しかし、同じｄｘ／ｄｙ＝１．１２５であるとき、Ｌｘ＝０．００１λ（ただしｎ＝２）程度にした場合、図１８に示すようにＮ＝２における９６０ＭＨｚの共振周波数において同じ面積のメアンダアンテナとペアノアンテナのゲインを比較すると、ペアノ曲線のほうがメアンダ曲線よりも約３ｄＢ程度強く放射していることがわかる。よって、電流進行方向に対し、ペアノ曲線を構成する方形の長辺の長さが０．００１λ程度になると、ペアノ曲線を使用することで同じ面積のメアンダ曲線のアンテナより放射が３ｄＢ強くすることができた。 According to the wireless identification tag according to the present embodiment, the antenna element 26 in the antenna part is a Peano-curved antenna that is bent a plurality of times and fills part of the surface of the dielectric, so that an efficient antenna can be used. Can be formed. That is, in the above formulas (4) and (5), when dx ≠ dy, the total length Sn of the Peano curve is expressed by the following formulas (6) and (7) with respect to n.

However, considering the combination of N units in FIGS. 5 and 6 and connection to the power feeding unit, dy is added to the total length of the normally known Peano curve. Further, in the case of this antenna, NSn = mλ / 2 needs to be satisfied, and it is usually difficult to give a phase difference of 180 degrees to the current on the adjacent line. Here, N is basically a natural number, but may not be the case in consideration of the resonance frequency and the required size of the antenna element. For example, N is a value of about 1 to 10, but is determined by the relationship between dx and dy. In addition, m is a natural number, and m = 1 should be considered in consideration of a small antenna. FIG. 14 is an example of a meander curve when dx / dy = 1.125 for n = 2 and N = 6, as in the case of the Peano curve of FIG. When these are compared, as shown in FIG. 15, the S11 characteristic is 433 MHz. In this case, although Lx = 0.005λ, there is almost no difference in the gain characteristics of this frequency as shown in FIG. However, when the same dx / dy = 1.125, when Lx = 0.001λ (where n = 2), a meander antenna having the same area at a resonance frequency of 960 MHz at N = 2 as shown in FIG. And the gain of the Peano antenna, it can be seen that the Peano curve radiates about 3 dB stronger than the meander curve. Therefore, when the length of the long side of the square forming the Peano curve is about 0.001λ with respect to the current traveling direction, the use of the Peano curve may increase the radiation by 3 dB compared to the meander antenna of the same area. did it.

  In the above embodiment, the case where the power supply terminal is a coplanar line has been described as an example. However, in the present invention, the power supply terminal 30 of the antenna 20 is connected between the antenna element 26 and the transmission / reception means. You may form by a microstrip line.

  In the above-described embodiment, the case where the antenna element is formed in a Peano curve shape has been described as an example. However, in the present invention, a half-wave dipole antenna or a meander curve antenna may be used. . Further, the antenna may be a linear element having a Hilbert curve shape, which is one of space filling curves covering the space.

  In the above-described embodiment, the active type wireless identification tag having a built-in battery has been described as an example. However, in the present invention, a passive type that is turned on by electromagnetic energy from the main device side may be used.

It is a side view which shows one Embodiment of the radio | wireless identification tag which concerns on this invention. It is a top view which shows an example of the antenna part applied to embodiment of FIG. It is sectional drawing which shows an example of the antenna part applied to embodiment of FIG. It is a schematic diagram for demonstrating the shape of the antenna element applied to embodiment of FIG. It is a schematic diagram for demonstrating the shape of the antenna element applied to embodiment of FIG. It is a top view which shows the connection part of the antenna element and tag main body which are applied to embodiment of FIG. It is a graph for demonstrating the formation method of the ground terminal applied to embodiment of FIG. It is a graph for demonstrating the formation method of the ground terminal applied to embodiment of FIG. It is a graph for demonstrating the formation method of the ground terminal applied to embodiment of FIG. It is a graph for demonstrating the formation method of the ground terminal applied to embodiment of FIG. It is a schematic diagram for demonstrating the effect of embodiment of FIG. It is a graph for demonstrating the effect of embodiment of FIG. It is a graph for demonstrating the effect of embodiment of FIG. It is a top view which shows the other example of the antenna element applied to the radio | wireless identification tag of this invention. It is a monitor screen waveform diagram for demonstrating the effect of embodiment of FIG. It is a monitor screen waveform diagram for demonstrating the effect of embodiment of FIG. It is a monitor screen waveform diagram for demonstrating the effect of embodiment of FIG. It is a monitor screen waveform diagram for demonstrating the effect of embodiment of FIG. In the antenna of embodiment of FIG. 1, it is a top view which shows a connection part with the tag main body using another antenna element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tag main body 20 Antenna 22 Reflector 24 Dielectric material 26 Antenna element 30 Feeding terminal 301 Waveguide 30A Coplanar line 40 Grounding terminal 60 Microstrip line

Claims (20)

An antenna structure in a small wireless device that is mounted at a desired location and transmits a predetermined signal,
A dielectric formed in a flat plate shape;
A linear antenna element provided on the surface of the dielectric;
A feeding terminal provided at an end of the antenna element and connected to a small wireless device;
A ground terminal provided in the vicinity of the power supply terminal and spaced from the power supply terminal by a predetermined gap;
An antenna structure in a small wireless device, comprising: a reflector provided on a back surface of a flat dielectric and reflecting an electromagnetic wave from an antenna element. The antenna structure according to claim 1, wherein
The feed terminal is a waveguide in which a ground terminal having a conductive foil pattern formed on the surface of the dielectric is provided on both sides with a gap, and the conductor foil is patterned on the surface of the dielectric together with the antenna element together with the ground terminal. 2. The antenna structure in a small wireless device according to claim 1, wherein the antenna structure is constituted by a waveguide forming a coplanar line. The antenna structure according to claim 1, wherein
An antenna structure in a small wireless device, wherein the power supply terminal is formed by a microstrip line connecting between the antenna element and the small wireless device. The antenna structure according to any one of claims 1 to 3,
An antenna structure in a small wireless device, wherein the antenna element is a half-wave dipole antenna. The antenna structure according to any one of claims 1 to 3,
An antenna structure in a small wireless device, wherein the antenna element is a Peano curve antenna that is bent a plurality of times to fill a part of a surface of a dielectric. The antenna structure according to any one of claims 1 to 3,
An antenna structure in a small wireless device, wherein the antenna element is a meander curved antenna formed by bending a plurality of rectangles. The antenna structure according to any one of claims 1 to 6,
An antenna structure in a small wireless device, wherein the small wireless device is a wireless identification tag that transmits an identification code of the own device to a main device. In the wireless identification tag that transmits the identification signal of its own device to the main device,
Including a signal generation means for generating an identification signal, a transmission / reception means for transmitting / receiving a signal including the identification signal from the signal generation means to / from the main apparatus, and an antenna part connected to the transmission / reception means,
The antenna portion includes a flat dielectric, a linear antenna element formed on the surface of the dielectric, a feeding terminal formed at the end of the antenna element, and a predetermined interval on both sides of the feeding terminal. And a grounding terminal formed on the back surface of the dielectric, and a metal reflector formed on the back surface of the dielectric. The wireless identification tag according to claim 8, wherein
The power feeding terminal of the antenna part is a coplanar line-shaped waveguide in which a conductor foil is patterned on the surface of the dielectric together with the antenna element.
The radio frequency identification tag, wherein the ground terminal is a coplanar line-shaped portion in which a conductive foil is patterned on the surface of a dielectric. The wireless identification tag according to claim 8, wherein
The wireless identification tag, wherein the power feeding terminal of the antenna portion is formed by a microstrip line connecting the antenna element and the transmitting / receiving means. The wireless identification tag according to any one of claims 8 to 10,
The wireless identification tag, wherein the antenna element of the antenna part is a half-wave dipole antenna. The wireless identification tag according to any one of claims 8 to 10,
The radio identification tag according to claim 1, wherein the antenna element of the antenna portion is a Peano curve antenna that is bent a plurality of times and is partially filled with a space on the surface of the dielectric. The wireless identification tag according to any one of claims 8 to 10,
The wireless identification tag according to claim 1, wherein the antenna element of the antenna part is a meander curved antenna formed by bending a plurality of rectangles. In the method of forming an antenna part in a small wireless device that is mounted at a desired location and transmits a predetermined signal, the method includes:
Forming a linear antenna element on the surface of the dielectric formed in a flat plate shape;
Providing a metal reflector on the back of the dielectric;
Providing a feed terminal connected to the small wireless device at the end of the antenna element when forming the antenna element;
Providing a ground terminal in the vicinity of the power supply terminal of the linear antenna with a predetermined gap from the power supply terminal,
A method for forming an antenna part in a small wireless device, wherein a desired resonance frequency of an antenna element is obtained by adjusting a distance between a feeding terminal and an installation terminal. The method of forming an antenna part according to claim 14,
The power feeding terminal, together with the antenna element, forms a coplanar line-shaped waveguide by patterning a conductor foil on the surface of the dielectric,
A method of forming an antenna part in a small wireless device, wherein the ground terminal forms a coplanar line-like part by patterning a conductor foil on the surface of a dielectric. The method of forming an antenna part according to claim 14,
A method of forming an antenna part in a small wireless device, wherein the power supply terminal connects the antenna element and the small wireless device by a microstrip line. In the formation method of the antenna site | part in any one of Claim 14 thru | or 16,
The antenna element is formed by a half-wave dipole antenna. In the formation method of the antenna site | part in any one of Claim 14 thru | or 17,
A method for forming an antenna part in a small wireless device, wherein the antenna element is formed by a Peano curve-shaped antenna that is bent a plurality of times and partially fills a part of the surface of a dielectric. In the formation method of the antenna site | part in any one of Claim 14 thru | or 17,
A method for forming an antenna portion in a small wireless device, wherein the antenna element is formed by a meander-curved antenna formed by bending a plurality of antennas into a rectangular shape. In the formation method of the antenna site | part in any one of Claim 14 thru | or 19,
The method for forming an antenna part in a small wireless device, wherein the small wireless device is a wireless identification tag that transmits an identification code of the own device to a main device.

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