CN106058434B - A kind of antenna applied to mobile terminal - Google Patents

Abstract

The invention discloses a kind of antennas applied to mobile terminal, including upper layer and lower layer printed board；Lower layer's printed board front is printed with monopole radiating element, and monopole radiating element is electrically connected metal feeding point；A part for covering radiator of the copper as antenna of lower layer's printing back, while being used as the main floor of antenna；Upper layer printed board front is printed with short-circuit radiating element, and what short-circuit radiating element was connected to lower layer's printing back covers copper.By distinguishing the sub- radiating element of printed monopole and short-circuit radiating element in upper layer and lower layer printed board, the resonance for generating different frequency allows antenna to work in multiband, effectively reduces the area of antenna occupancy, make the compact-sized of antenna, is advantageously implemented the miniaturization of antenna.The monopole radiating element of directly excitation lower layer, and it is coupled to the short-circuit radiating element on upper layer, distributed LC match circuit may be implemented, increase input port capacitive reactance, and introduce distribution induction reactance characteristic.

Description

An antenna applied to a mobile terminal

technical field

The present invention relates to the field of mobile terminal communication, in particular to an antenna applied to a mobile terminal.

Background technique

Antenna, as an important part of mobile terminal, is an important radio device that transmits and receives electromagnetic waves. Its performance is directly related to the communication quality of the communication system, and plays a very important role in the overall performance of mobile communication. The continuous upgrading of today's mobile communication systems provides new index requirements for mobile terminal antennas. The design and research of new miniaturized antennas that meet wider bandwidth, multi-frequency bands, high efficiency and can better adapt to various requirements of the system are the current domestic and foreign terminal antennas. important research topics in the field.

Today, the coexistence of various mobile communication systems and the signals of peripheral wireless devices such as Bluetooth, Wi-Fi and GPS make the antennas need to work in multiple frequency bands, and a wider bandwidth is required to ensure good communication quality. Currently, it is widely used in mobile terminals. There are basic antenna forms such as monopole antenna, PIFA antenna, IFA antenna, loop antenna, etc., but these basic forms of antenna have been difficult to meet the increasing demand for high-performance miniaturized antennas.

SUMMARY OF THE INVENTION

In order to meet the requirements of wide bandwidth and multiple frequency bands of the antenna and realize the miniaturization of the antenna, the present invention provides an antenna applied to a mobile terminal.

The antenna applied to the mobile terminal provided by the present invention includes upper and lower printed boards;

The monopole radiating element is printed on the front of the lower printed board, and the monopole radiating element is electrically connected to the metal feed point; the copper cladding on the back of the lower printed board is used as a part of the radiator of the antenna, Also serves as the main floor for the antenna;

A short-circuit radiation unit is printed on the front side of the upper printed board, and the short-circuit radiation unit is connected to the copper cladding on the back of the lower printed board.

Wherein, inductors and/or capacitors are loaded between the upper and lower printed boards.

Wherein, the antenna further includes a bent radiator;

One end of the bent radiation sheet is connected to the short-circuit radiation unit, and the other end extends out of the plane where the short-circuit radiation unit is located.

Wherein, the monopole radiating element is used to generate high frequency resonance in the range of 1630-2780MHz; the short-circuit radiation element is used to generate low frequency resonance in the range of 680-1080MHz.

Wherein, the monopole radiation unit is an inverted-F type, and is composed of a first microstrip line, a second microstrip line and a third microstrip line printed on the front side of the lower printed board; wherein,

The first microstrip line and the second microstrip line are parallel to each other and are respectively perpendicular to the third microstrip line, and the first end of the first microstrip line is connected to the third microstrip line. The first end, the first end of the second microstrip line is connected to the third microstrip line and the distance from the second end of the third microstrip line is 19mm, and the distance of the second microstrip line is 19 mm. The second end is electrically connected to the metal feed point;

The first microstrip line is 6mm long and 4mm wide; the second microstrip line is 7mm long and 1.5mm wide; the third microstrip line is 30.5mm long and 2.5mm wide; the metal feed point is rectangular , 2mm long and 1.5mm wide.

Wherein, the short-circuit radiation unit is T-shaped and consists of a fourth microstrip line and a fifth microstrip line printed on the front side of the upper printed board; wherein,

The fourth microstrip line is perpendicular to the fifth microstrip line, and the first end of the fourth microstrip line is connected to the fifth microstrip line and is the first end of the fifth microstrip line The distance between the ends is 7.5mm, and the distance from the second end of the fifth microstrip line is 31.5mm;

The fourth microstrip line is 11 mm long and 1 mm wide; the fifth microstrip line is 40 mm long and 3 mm wide.

Wherein, the second end of the fourth microstrip line is loaded with an inductance and connected to the copper cladding on the back of the lower printed board through a first metallized via; the inductance size is 100nH;

The first end of the fifth microstrip line is loaded with a capacitor and is connected to the first end of the third microstrip line through the second metallized via; the size of the capacitance is 200pF.

Wherein, the bent radiating sheet is rectangular, 50mm long and 6mm wide;

The long side of the bent radiating sheet is connected to the fifth microstrip line, and the broad side of the bent radiating sheet is aligned with the first end of the fifth microstrip line;

The bent radiating sheet is perpendicular to the upper printed board.

The third microstrip line is parallel to the fifth microstrip line, and the first end of the third microstrip line is vertically aligned with the first end of the fifth microstrip line.

Wherein, the upper and lower printed boards are rectangular glass fiber epoxy resin copper clad laminates with a height of 140mm, a width of 70mm, a dielectric constant of 4.4 and a thickness of 0.8mm;

The size of the clearance space occupied by the antenna is 15mm*50mm, and the size of the clear floor of the system is 125mm*70mm;

The two sides of the first end of the fifth microstrip line are respectively aligned with the top edge and the side edge of the upper-layer printed board.

The beneficial effect of the embodiment of the present invention is: by printing the monopole radiation unit and the short-circuit radiation unit on the upper and lower printed boards respectively, the monopole radiation unit and the short-circuit radiation unit can generate resonances of different frequencies, so that the antenna can Works in multiple frequency bands; monopole radiating element and short-circuit radiating element are placed on top of one another, reducing the area occupied by the antenna, making the structure of the antenna compact and realizing the miniaturization of the antenna; by directly exciting the monopole radiation in the lower layer The unit is coupled to the short-circuit radiation unit on the upper layer, which can realize a distributed LC matching circuit. Coupling and feeding will increase the capacitive reactance of the input port, and the short-circuit radiation unit will introduce distributed inductance characteristics.

In a preferred embodiment, by loading lumped parameter elements, such as inductors and capacitors, between the upper and lower printed boards, and by adjusting the value of the lumped parameter elements, the resonant frequency of the antenna can be changed, the bandwidth can be widened, and the antenna can be The specific frequency band required can obtain better port matching; it is not necessary to change the resonant frequency by designing complex antenna shapes, which simplifies the shape of the antenna, makes the antenna easier to process and debug, and is beneficial to control costs and facilitate mass production and processing.

In another preferred embodiment, a bent radiating sheet is connected to the short-circuit radiating element, and the other end of the bent radiating sheet extends out of the plane where the short-circuit radiating element is located, thereby increasing the radiation area of the antenna and increasing the radiation impedance of the antenna. , and the shielding effect of the antenna main floor on the antenna radiator is reduced because the shielding effect of the antenna main floor on the bent radiator is reduced.

Description of drawings

FIG. 1 is a perspective perspective view of an antenna with a floor for use in a mobile terminal according to an embodiment of the present invention;

FIG. 2 is a perspective perspective view of an antenna applied to a mobile terminal without a floor according to an embodiment of the present invention;

3 is a schematic structural diagram of a monopole radiating unit applied to an antenna of a mobile terminal according to an embodiment of the present invention;

4 is a schematic structural diagram of a short-circuit radiation unit applied to an antenna of a mobile terminal according to an embodiment of the present invention;

FIG. 5 is a simulation S11 curve diagram of an antenna applied to a mobile terminal provided by a preferred embodiment of the present invention;

Fig. 6 is a simulation pattern of an antenna applied to a mobile terminal provided by a preferred embodiment of the present invention, wherein Fig. 6(a) is a pattern in the x-y plane, Fig. 6(b) is a pattern in the y-z plane, and Fig. 6 (c) is the orientation diagram of the x-z plane.

Detailed ways

The design concept of the present invention is as follows: adopting coupled feeding and short-circuit radiating elements to realize a distributed LC matching circuit, loading lumped parameter elements on this basis, and changing the frequency of the antenna resonance point by adjusting the lumped parameter value to obtain the required work frequency, so as to realize a wide-band mobile terminal antenna, which can cover multiple frequency bands of mobile communication services, and at the same time meet the needs of antenna miniaturization.

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view of an antenna applied to a mobile terminal with a floor according to an embodiment of the present invention; FIG. 2 is a perspective view of an antenna applied to a mobile terminal without a floor according to an embodiment of the present invention. With reference to FIG. 1 and FIG. 2 , an antenna applied to a mobile terminal provided by an embodiment of the present invention includes a lower-layer printed board 1 and an upper-layer printed board 2 .

The monopole radiation unit 7 is printed on the front side of the lower printed board 1 . The monopole radiating element 7 is electrically connected to the metal feeding point 10 . The copper cladding on the back of the lower printed board 1 is used as part of the radiator of the antenna to increase the radiation area of the antenna. At the same time, the copper cladding on the back of the printed board 1 is also used as the main floor of the antenna, simulating the system of mobile terminal equipment land.

A short-circuit radiation unit 4 is printed on the front side of the upper printed board 2 . The backside of the upper printed board 2 has no copper cladding, and the short-circuit radiation unit 4 is connected to the copper cladding on the backside of the lower printed board 1 . Since the short-circuit radiating element 4 is connected to the main floor of the antenna, it is called a short-circuit radiating element.

The monopole radiating element 7 and the short-circuit radiating element 4 can generate resonances of different frequencies, so that the antenna can work in multiple frequency bands. Compared with the existing radiation branches of the antenna made in the same plane, the short-circuit radiation unit 4 and the monopole radiation unit 7 are respectively printed on the upper and lower printed boards, and placed in an overlapping manner, which reduces the occupation of the antenna. The area of the antenna is compact, which is conducive to realizing the miniaturization of the antenna. The monopole radiating element 7 of the lower layer is directly excited through the feeding point 10, and is coupled to the short-circuit radiating element 4 of the upper layer. To implement a distributed LC matching circuit, the coupled feed will increase the capacitive reactance of the input port, and the short-circuit radiating element 4 will introduce distributed inductive reactance characteristics.

Preferably, inductance and/or capacitance are loaded between the lower printed board 1 and the upper printed board 2 . For example, a capacitor 5 can be loaded between the monopole radiating element 7 and the short-circuit radiating element 4, and an inductance 8 can be loaded between the short-circuit radiating element 4 and the main floor of the antenna. Adjusting the capacitance value of capacitor 5 and the inductance value of inductor 8 can change the frequency of the resonance point of the antenna, broaden the bandwidth, and enable the antenna to obtain better port matching in the specific frequency band required. Due to the loading of lumped parameter elements such as inductors and capacitors, the required resonant frequency can be obtained by adjusting the inductance and capacitance values of the inductors and capacitors. It is not necessary to change the resonant frequency by designing complex antenna shapes, which can simplify the shape of the antenna and make the antenna It is easier to process and debug, which is beneficial to control costs and facilitate mass production and processing.

Further preferably, the antenna applied to the mobile terminal provided by the embodiment of the present invention further includes a bent radiating sheet 3 . One end of the bent radiation sheet 3 is connected to the short-circuit radiation unit 4, and the other end extends out of the plane where the short-circuit radiation unit 4 is located. Bending the radiating sheet 3 increases the radiation area of the antenna and also increases the radiation impedance of the antenna, and the bending radiating sheet 3 extends beyond the plane where the short-circuit radiating element 4 is located. In other ways, the shielding effect of the antenna main floor on the antenna radiator is reduced because the shielding effect of the antenna main floor on the bent radiator is reduced.

FIG. 3 is a schematic structural diagram of a monopole radiating unit applied to an antenna of a mobile terminal according to an embodiment of the present invention; FIG. 4 is a structure of a short-circuit radiating unit applied to an antenna of a mobile terminal according to an embodiment of the present invention Schematic diagram; in conjunction with FIG. 3 and FIG. 4, an antenna provided by a preferred embodiment of the present invention can cover GSM900/1800/1900/UMTS, LTE700/LTE2300/2500 and WLAN2.4 frequency bands, and the monopole radiation unit 7 is used to generate high The frequency resonance range is 1630-2780MHz; the short-circuit radiation unit 4 is used to generate low-frequency resonance with a range of 680-1080MHz, which can cover the requirements of multiple frequency bands of mobile communication services while realizing the miniaturization of the antenna.

In a preferred embodiment, the monopole radiation unit 7 is an inverted-F type, and is composed of a first microstrip line, a second microstrip line and a third microstrip line printed on the front surface of the lower printed board 1 . The first microstrip line and the second microstrip line are parallel to each other and are respectively perpendicular to the third microstrip line, the first end of the first microstrip line is connected to the first end of the third microstrip line, the second microstrip line is The first end is connected to the third microstrip line; the second end of the second microstrip line is electrically connected to the metal feed point.

The short-circuit radiation unit 4 is T-shaped and consists of a fourth microstrip line and a fifth microstrip line printed on the front side of the upper printed board; the fourth microstrip line is perpendicular to the fifth microstrip line, and the fourth microstrip line is One end is connected to the fifth microstrip line.

According to the monopole as an effective quarter-wavelength radiator, first determine the size of the monopole radiation unit 7 so that the resonant frequency of the monopole radiation unit 7 is around 1.8 GHz, and then determine the size of the short-circuit radiation unit 4 , so that the resonant frequency of the short-circuit radiation element 4 is around 1 GHz. After the size of the monopole radiation unit 7 and the short-circuit radiation unit 4 is determined, the monopole radiation unit 7 and the short-circuit radiation unit 4 are combined together, and the size is further optimized and adjusted through simulation and other methods until it meets the needs. performance indicators.

In a specific embodiment, the dimensions of the monopole radiation unit 7 and the short-circuit radiation unit 4 are specifically: the first microstrip line is 6 mm long and 4 mm wide; the second microstrip line is 7 mm long and 1.5 mm wide; the third microstrip line is 7 mm long and 1.5 mm wide; The wire is 30.5mm long and 2.5mm wide; the metal feed point is rectangular, 2mm long and 1.5mm wide. The distance between the first end of the second microstrip line and the second end of the third microstrip line is 19 mm.

The distance between the first end of the fourth microstrip line and the first end of the fifth microstrip line is 7.5 mm, and the distance from the second end of the fifth microstrip line is 31.5 mm. The fourth microstrip line is 11mm long and 1mm wide; the fifth microstrip line is 40mm long and 3mm wide.

The third microstrip line is parallel to the fifth microstrip line, and the first end of the third microstrip line is vertically aligned with the first end of the fifth microstrip line.

In another preferred embodiment, the second end of the fourth microstrip line is loaded with inductance and connected to the copper cladding on the backside of the lower printed board through the first metallized via, and the first end of the fifth microstrip line is loaded with capacitance and The second metallized via is connected to the first end of the third microstrip line, and the values of the inductance and capacitance are adjusted by simulation, the resonant frequency of the antenna can be changed, and the bandwidth can be expanded to obtain the required frequency band. In this embodiment, the inductance value of the inductor is 100nH, and the capacitance value of the capacitor is 200pF.

The bent radiant sheet is rectangular, 50mm long and 6mm wide, the long side of the bent radiant sheet is connected to the fifth microstrip line, and the wide side of the bent radiant sheet is aligned with the first end of the fifth microstrip line. The bent radiator extends upward perpendicular to the upper printed board to increase the radiation area and radiation impedance of the antenna and reduce the shielding effect of the main floor of the antenna. Of course, the bent radiating sheet can also be non-vertical, such as extending in an arc shape to the outside of the plane where the short-circuit radiating element is located, which can play the same role, and the principle is the same, and will not be repeated here.

The lower printed board 1 and the upper printed board 2 are both rectangular glass fiber epoxy resin copper clad laminates, with a height of 140 mm, a width of 70 mm, a dielectric constant of 4.4, and a thickness of 0.8 mm. The size of the clearance space occupied by the antenna provided by this preferred embodiment is 15mm*50mm, and the size of the clear floor of the system is 125mm*70mm. The monopole radiation unit 7 and the short-circuit radiation unit 4 are arranged at the upper left corner of the printed board, and the two sides of the first end of the fifth microstrip line are respectively aligned with the top and side edges of the upper printed board. Of course, the position where the antenna is set is set according to the distribution of the internal components of the mobile terminal, and is not limited to the above-mentioned positions, as long as there is sufficient clearance and floor, and the interference is small.

FIG. 5 is a simulation S11 graph of an antenna applied to a mobile terminal provided by a preferred embodiment of the present invention, wherein the solid line is the S11 diagram of the antenna after the lumped parameter element is loaded, and the dotted line is the antenna without the lumped parameter element loaded. Figure S11, S11 is the input return loss. The simulation results show that the absolute bandwidth of the antenna provided by the above preferred embodiment is 400M in the low frequency band around 1 GHz after the lumped parameter element is loaded, which is twice the absolute bandwidth of the antenna when the lumped parameter element is not loaded; the antenna is loaded with the lumped parameter. After the component, the coverage bandwidth in the high frequency band is 1630MHz to 2780MHz, while the bandwidth of the component without lumped parameters only covers 2550MHz to 2650MHz.

FIG. 6 is a simulation pattern of an antenna applied to a mobile terminal provided by a preferred embodiment of the present invention, wherein: FIG. 6(a) is a pattern on the x-y plane, and FIG. 6(b) is a pattern on the y-z plane. 6(c) is the direction map of the x-z plane. Three frequency points of 0.9 GHz, 2.0 GHz and 2.5 GHz are selected in FIG. 6 . It can be seen from FIG. 6 that the antenna provided by the embodiment of the present invention can meet the performance requirements at these three frequency points, and has good performance in all directions.

To sum up, the present invention provides an antenna applied to a mobile terminal, which has the following beneficial effects compared with the prior art:

1. By printing the monopole radiating element and the short-circuit radiating element on the upper and lower printed boards respectively, the monopole radiating element and the short-circuit radiating element can generate resonances of different frequencies, so that the antenna can work in multiple frequency bands; The upper and lower layers of the sub-radiation unit and the short-circuit radiation unit are overlapped, which reduces the area occupied by the antenna, makes the antenna compact, and realizes the miniaturization of the antenna. The short-circuit radiating element can realize a distributed LC matching circuit. Coupling feed will increase the capacitive reactance of the input port, and the short-circuit radiating element will introduce distributed inductance characteristics.

2. By loading lumped parameter components, such as inductors and capacitors, between the upper and lower printed boards, and by adjusting the value of the lumped parameter components, the frequency of the resonance point of the antenna can be changed, and the bandwidth can be broadened, so that the antenna can obtain the required specific frequency band. Better port matching; it is not necessary to change the resonant frequency by designing complex antenna shapes, which simplifies the shape of the antenna, makes the antenna easier to process and debug, and is beneficial to control costs and facilitate mass production and processing.

3. By connecting a bent radiator to the short-circuit radiating element, the other end of the bent radiator extends out of the plane where the short-circuit radiating element is located, which increases the antenna radiation area and also increases the antenna radiation impedance. The main floor shields the bent radiator, thereby reducing the shielding effect of the antenna main floor on the antenna radiator.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims (10)

1. An antenna applied to a mobile terminal, wherein the antenna comprises an upper and lower two-layer printed circuit board; The monopole radiating element is printed on the front of the lower printed board, and the monopole radiating element is electrically connected to the metal feed point; the copper cladding on the back of the lower printed board is used as a part of the radiator of the antenna, Also serves as the main floor for the antenna; A short-circuit radiation unit is printed on the front of the upper printed board, and the short-circuit radiation unit is connected to the copper cladding on the back of the lower printed board; the monopole radiation unit and the short-circuit radiation unit are placed overlapping, and the single The pole radiation unit and the short-circuit radiation unit generate resonances of different frequencies. 2 . The antenna applied to a mobile terminal according to claim 1 , wherein an inductor and/or a capacitor is loaded between the upper and lower printed boards. 3 . 3. The antenna applied to a mobile terminal according to claim 2, wherein the antenna further comprises a bent radiator; One end of the bent radiation sheet is connected to the short-circuit radiation unit, and the other end extends out of the plane where the short-circuit radiation unit is located. 4. The antenna applied to a mobile terminal according to claim 3, wherein the monopole radiating element is used to generate high frequency resonance, and the range is 1630-2780MHz; the short-circuit radiating element is used to generate low frequency resonance, The range is 680-1080MHz. 5. The antenna applied to a mobile terminal according to claim 4, wherein, The monopole radiation unit is an inverted-F type, and is composed of a first microstrip line, a second microstrip line and a third microstrip line printed on the front side of the lower printed board; wherein, The first microstrip line and the second microstrip line are parallel to each other and are respectively perpendicular to the third microstrip line, and the first end of the first microstrip line is connected to the third microstrip line. The first end, the first end of the second microstrip line is connected to the third microstrip line and the distance from the second end of the third microstrip line is 19mm, and the distance of the second microstrip line is 19 mm. The second end is electrically connected to the metal feed point; The first microstrip line is 6mm long and 4mm wide; the second microstrip line is 7mm long and 1.5mm wide; the third microstrip line is 30.5mm long and 2.5mm wide; the metal feed point is rectangular , 2mm long and 1.5mm wide. 6. The antenna applied to a mobile terminal according to claim 5, wherein, The short-circuit radiation unit is T-shaped and consists of a fourth microstrip line and a fifth microstrip line printed on the front side of the upper printed board; wherein, The fourth microstrip line is perpendicular to the fifth microstrip line, and the first end of the fourth microstrip line is connected to the fifth microstrip line and is the first end of the fifth microstrip line The distance between the ends is 7.5mm, and the distance from the second end of the fifth microstrip line is 31.5mm; The fourth microstrip line is 11 mm long and 1 mm wide; the fifth microstrip line is 40 mm long and 3 mm wide. 7. The antenna applied to a mobile terminal according to claim 6, wherein, The second end of the fourth microstrip line is loaded with an inductance and is connected to the copper cladding on the back of the lower printed board through a first metallized via; the inductance is 100nH; The first end of the fifth microstrip line is loaded with a capacitor and is connected to the first end of the third microstrip line through the second metallized via; the size of the capacitance is 200pF. 8. The antenna applied to a mobile terminal according to claim 6, wherein, The bent radiating sheet is rectangular, 50mm long and 6mm wide; The long side of the bent radiating sheet is connected to the fifth microstrip line, and the broad side of the bent radiating sheet is aligned with the first end of the fifth microstrip line; The bent radiating sheet is perpendicular to the upper printed board. 9. The antenna applied to a mobile terminal according to claim 7 or 8, wherein, The third microstrip line is parallel to the fifth microstrip line, and the first end of the third microstrip line is vertically aligned with the first end of the fifth microstrip line. 10. The antenna applied to a mobile terminal according to claim 9, wherein, The upper and lower printed boards are rectangular glass fiber epoxy resin copper clad laminates with a height of 140mm, a width of 70mm, a dielectric constant of 4.4 and a thickness of 0.8mm; The size of the clearance space occupied by the antenna is 15mm*50mm, and the size of the clear floor of the system is 125mm*70mm; The two sides of the first end of the fifth microstrip line are respectively aligned with the top edge and the side edge of the upper-layer printed board.