TW201519510A - Planar antennas - Google Patents

Abstract

This invention discloses a planar antenna to solve the problems of area overhead. The planar antenna comprises a baseboard, an antenna unit, a first grounding, and a second grounding. The antenna unit has a feeding portion and a radiating portion. The radiating portion connects with the feeding portion. The first grounding has a hollow portion. The hollow portion and the radiating portion are mirror symmetry along the extending direction of the feeding portion. The second grounding is opposite to the radiating portion. The antenna unit, the first grounding, and the second grounding are disposed on the same face of the baseboard. The feeding portion is disposed between the first grounding and the second grounding. Furthermore, this invention also discloses a MIMO antenna extended from the said planar antennas. Thus, the above-mentioned problem can actually be solved.

Description

Planar antenna

The present invention relates to a planar antenna; and more particularly to a planar antenna suitable for wide frequency operation.

With the increasing demand for wireless transmission, such as 4th generation mobile communication system (Long-term evolution, LTE) and WiMAX, the single-input and single-output (SISO) channel has a channel. The bottleneck of capacity, therefore, it is necessary to develop antenna technologies such as broadband and multi-input and multi-output (MIMO) for a receiving end to receive multiple signals transmitted by one transmitting end to increase data throughput. Volume (Throughput). However, conventional multi-antenna technology still has some shortcomings.

For example, the Korean Patent Publication No. KR100699472B1 "Planar MIMO Array Antenna" invention patent discloses a conventional planar antenna that utilizes isolation elements between antennas to achieve good isolation between two antennas. The distance can be effective. This will increase the overall system size, and the isolation element will cause a drop in antenna radiation efficiency.

In addition, U.S. Patent No. 7,476,069, "MONOPOLE ANTENNA APPLICABLE TO MIMO SYSTME" invention patent, discloses another conventional planar antenna, which uses a certain distance between antenna elements to form a multi-antenna system, but causes an increase in overall area, and Not applicable to broadband operation

In view of this, in the practical application of the conventional multi-antenna architecture, in addition to the "area product used" In addition to the problems of "too big" and "need to use isolation components", the demand for "broadband operation performance" has caused many limitations and shortcomings in actual use. It is inconvenient and needs further improvement to enhance its practicability. .

The main object of the present invention is to provide a planar antenna suitable for broadband operation.

A second object of the present invention is to provide a planar antenna that can reduce the area occupied.

Another object of the present invention is to provide a planar antenna that does not require isolation elements.

The present invention provides a planar antenna comprising: a substrate; an antenna unit having a feeding portion and a radiating portion, the radiating portion connecting the feeding portion; a first grounding body having a hollow portion, the hollow portion and the radiation The portion is mirror-symmetrical along the extending direction of the feeding portion; and a second grounding body is opposite to the radiating portion; wherein the antenna unit, the first grounding body and the second grounding system are disposed on the same surface of the substrate, The feeding portion is disposed between the first grounding body and the second grounding body.

Preferably, the radiating portion has a first edge, a second edge and a matching edge, the first edge is connected to the feeding portion, the second edge is opposite to the first edge, and the matching edge is connected to the second edge The length of the second edge is less than the length of the first edge.

Preferably, the matching edge is a curved edge.

Preferably, the hollow portion has a third edge, a fourth edge and a mating edge, and an opening is formed between the third edge and the mating edge toward the radiation portion, the fourth edge being opposite to the third edge The mating edge is coupled to the fourth edge, the length of the fourth edge being less than the length of the third edge.

Preferably, the matching edge is a curved edge.

Preferably, the first grounding body and the feeding portion have a first spacing, the second grounding body and the feeding portion have a second spacing, and the radiation portion and the second grounding body have a third pitch, the third pitch being greater than the second pitch and the first pitch.

The invention further provides a planar antenna, comprising: a substrate; a first antenna single a first feeding portion and a first radiating portion, the first radiating portion is connected to the first feeding portion; a second antenna unit has a second feeding portion and a second radiating portion, the second The radiating portion is connected to the second feeding portion; a central grounding body has a first hollow portion and a second hollow portion, and the first hollow portion and the first radiating portion are mirror-symmetrical along the extending direction of the first feeding portion The second hollow portion and the second radiating portion are mirror-symmetrical along the extending direction of the second feeding portion; a first side grounding body opposite to the first radiating portion; and a second side grounding body, and the The second radiating portion is opposite to each other; wherein the first antenna unit, the second antenna unit, the central grounding body, the first side grounding body, and the second side grounding system are disposed on a same surface of the substrate, the first A feed portion is disposed between the central grounding body and the first grounding body, and the second feeding portion is disposed between the central grounding body and the second grounding body.

Preferably, the first hollow portion and the second hollow portion have an axis of symmetry The central grounding body is provided with a slot, and the slot is mirror symmetrical along the axis of symmetry.

Preferably, the slot has a connecting section hole and two side section holes, and the connecting section is connected The two side segments are respectively located on opposite sides of the axis of symmetry.

Preferably, the first radiating portion and the second radiating portion respectively have a first side a first edge of the first radiating portion is connected to the first feeding portion, and a second edge of the first radiating portion is opposite to the first edge of the first radiating portion, the first edge a matching edge of a radiating portion is connected to the second edge of the first radiating portion, a first edge of the second radiating portion is connected to the second feeding portion, and a second edge of the second radiating portion is opposite to the second radiating portion An edge of the second radiating portion is coupled to the second edge of the second radiating portion, and the length of each of the second edges is smaller than the length of each of the first edges.

Preferably, each matching edge is a curved edge.

Preferably, the first hollow portion and the second hollow portion respectively have a third edge, a fourth edge and a mating edge, and the third edge of the first hollow portion and the first hollow portion Forming an opening between the mating edges toward the first radiating portion, a fourth edge of the first hollow portion is opposite to a third edge of the first hollow portion, and a mating edge of the first hollow portion is connected to the first hollow portion a fourth edge, a third opening of the second hollow portion and a mating edge of the second hollow portion form another opening toward the second radiating portion, the fourth edge of the second hollow portion and the second hollow The third edge of the portion is opposite, the mating edge of the second hollow portion is connected to the fourth edge of the second hollow portion, and the length of each fourth edge is smaller than the length of each third edge.

Preferably, each mating edge is a curved edge.

Preferably, the first grounding body and the first feeding portion have a first space The second grounding body and the second feeding portion have a first spacing, the first side grounding body and the first feeding portion have a second spacing, the second side grounding body and the second The second spacing is between the first side grounding body and the first radiating portion, and the third side grounding body and the second radiating portion have the third spacing. The third pitch is greater than the second pitch and the first pitch.

Preferably, the curved edge is a quarter of a circumference of a circle.

Preferably, the circle has a radius of 6.5 to 7 mm.

〔this invention〕

1‧‧‧Substrate

2‧‧‧Antenna unit

21‧‧‧Feeding Department

22‧‧‧ Radiation Department

221‧‧‧ first edge

222‧‧‧ second edge

223‧‧‧ matching edge

3‧‧‧First grounding body

31‧‧‧镂空部

311‧‧‧ third edge

312‧‧‧ fourth edge

313‧‧‧ Pairing edge

314‧‧‧ openings

4‧‧‧Second grounding body

5‧‧‧Substrate

6a‧‧‧First antenna unit

61a‧‧‧First Feeding Department

62a‧‧‧First Radiation Department

6b‧‧‧second antenna unit

61b‧‧‧Second Feeding Department

62b‧‧‧Second Radiation Department

7‧‧‧Central grounding body

71a‧‧ First First Department

71b‧‧‧Second Office

72‧‧‧ slots

721‧‧‧Connection section hole

722‧‧‧Side section hole

8a‧‧‧First side grounding body

8b‧‧‧Second side grounding body

C‧‧‧ central axis

D‧‧‧Distance

G1, G1’‧‧‧ first spacing

G2, G2’‧‧‧second spacing

G3, G3’‧‧‧ third spacing

L‧‧‧ length

L1, L2‧‧‧ length

L1’, L2’‧‧‧ length

W‧‧‧Width

X, Xa, Xb‧‧ symmetry axis

Fig. 1 is a perspective view showing the combination of the first embodiment of the planar antenna of the present invention.

Figure 2 is a top plan view of a first embodiment of a planar antenna of the present invention.

Fig. 3 is a graph showing the relationship between the reflection coefficient and the frequency response of the first embodiment of the planar antenna of the present invention.

Figure 4 is a top plan view of a second embodiment of the planar antenna of the present invention.

Fig. 5 is a graph showing the relationship between the reflection coefficient and the frequency response of the second embodiment of the planar antenna of the present invention.

Figure 6 is a graph showing the relationship between the isolation and the frequency response of the second embodiment of the planar antenna of the present invention.

The above and other objects, features and advantages of the present invention will become more apparent and obvious. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein the "antenna" as used throughout the present invention refers to an element for transmitting or receiving radio waves, and is a technique of the present invention. Those with ordinary knowledge in the field can understand.

"Feeding" as used throughout the text of the present invention means by wire or no The manner in which the line provides energy to the electronic component is understood by those of ordinary skill in the art to which the present invention pertains.

The "coplanar waveguide" (CPW) as described throughout the present invention refers to a dielectric substrate One of the surfaces is provided with a central conductor, and two conductors are disposed on both sides of the central conductor as grounding bodies for transmitting coplanar waves, as will be understood by those of ordinary skill in the art to which the present invention pertains.

"mirror symmetry" as used throughout the text of the present invention means In a two-dimensional space, if one side of an axis of symmetry has an object, one of the objects is a mirror image of the other object (ie, the shape is anastomosed), and so on, in the three-dimensional space, the axis of symmetry is a plane. It will be understood by those of ordinary skill in the art to which the present invention pertains.

Please refer to FIG. 1 , which is a combination of the first embodiment of the planar antenna of the present invention. Stereo picture. The planar antenna includes a substrate 1, an antenna unit 2, a first grounding body 3, and a second grounding body 4. The antenna unit 2, the first grounding body 3, and the second grounding are disposed on one surface of the substrate 1. The antenna unit 2 is disposed between the first grounding body 3 and the second grounding body 4 and formed with two spaces to feed signals to the antenna unit 2 by a coplanar waveguide (CPW). The substrate 1 is preferably made of an insulating material, such as polyimide or the like; the antenna unit 2, the first grounding body 3, and the second grounding body 4 are made of a conductive material, such as a metal. Wait. in In this embodiment, the length L and the width W (as shown in FIG. 2) of the substrate 1 are respectively 20 and 27 millimeters (mm), but not limited thereto.

Please refer to FIG. 2, which is a top view of the first embodiment of the planar antenna of the present invention. Figure. The antenna unit 2 has a feeding portion 21 and a radiating portion 22, and the feeding portion 21 is located between the first grounding body 3 and the second grounding body 4; the radiating portion 22 has a first edge 221, a first a second edge 222 and a matching edge 223, the first edge 221 is connected to the feeding portion 21, the second edge 222 is opposite to the first edge 221, and the matching edge 223 (such as a curved or rectangular edge, etc.) is connected to the first edge The two edges 222, the length L2 of the second edge 222 is smaller than the length L1 of the first edge 221, and therefore, the length of the matching edge 223 can be changed to meet the requirement of impedance matching. In this embodiment, the matching edge 223 is a curved edge as an implementation aspect, but not limited thereto, wherein the curved edge is a quarter of a circle, and the radius of the circle is r. The radius r can be 6.5 to 7 mm; in addition, the length of the feeding portion 21 can be 9 mm; the length L1 of the first edge 221 can be 10 mm; the length L2 of the second edge 222 can be selected as 3 to 3.5 mm, the distance D between the second edge 222 and the first edge 221 may be 9 mm.

Please refer to FIG. 2 again, wherein the first grounding body 3 and the antenna unit are A first spacing G1 is formed between the feeding portions 21 of the second portion, and the first grounding body 3 has a hollow portion 31, and the radiating portion 22 of the antenna unit 2 is along the extending direction of the feeding portion 21 ( The symmetry axis X) is mirror symmetry, and the hollow portion 31 has a third edge 311, a fourth edge 312 and a mating edge 313. The third edge 311 and the pairing edge 313 An opening 314 is formed to face the radiation portion 22, and the fourth edge 312 is opposite to the third edge 311. The pairing edge 313 (such as a curved or rectangular edge or the like) is connected to the fourth edge 312. The fourth edge 312 is connected. The length L2' is smaller than the length L1' of the third edge 311. In this embodiment, the lengths of the third edge 311 and the fourth edge 312 are the same as the first edge 221 and the second edge 222 of the radiating portion 22, respectively, and are not described herein; G1 can be selected to be 0.4mm mm, but not limited to this. Therefore, the hollow portion 31 and the radiating portion 22 can complement each other to satisfy the structural condition of the "complementary antenna", and the characteristic of wide frequency can be understood by those skilled in the art to which the present invention pertains.

Please refer to FIG. 2 again, wherein the second grounding body 4 and the antenna unit are A second spacing G2 is formed between the feeding portions 21 of the second portion, and the second grounding body 4 is opposite to the radiating portion 22 of the antenna unit 2, and a third portion is between the radiating portion 22 and the second grounding body 4. The pitch G3 is greater than the second pitch G2 and the first pitch G1. In this embodiment, the distance of the second spacing G2 is the same as the first spacing G1, and the third spacing G3 may be 3.5 millimeters, but not limited thereto.

Please refer to FIG. 3, which is a reflection of the first embodiment of the planar antenna of the present invention. A plot of the coefficient versus frequency response. It is understood by those skilled in the art that the smaller the S11 parameter (ie, the reflection coefficient), the more power is received by the antenna, that is, the better the impedance matching of the antenna, the general S11 parameter is less than -10 dB. The following represents that more than 90% of the power is received, so the S11 parameter is mostly -10dB as a good antenna design reference; as shown in FIG. 3, the frequency range of the S11 parameter of the first embodiment of the planar antenna of the present invention is less than -10dB. 3.8 to 9 GHz, that is, the antenna unit has a reflection coefficient value of less than -10 dB in the frequency range of 3.8 to 9 GHz. Therefore, the antenna unit of the embodiment has a good reflection coefficient. The number of the antenna units in the above-mentioned first embodiment can be further expanded to form a multi-input and output antenna. The following two antenna units are described as the second embodiment, but not limited thereto.

Please refer to FIG. 4, which is a top view of the second embodiment of the planar antenna of the present invention. Figure. The planar antenna includes a substrate 5, a first antenna unit 6a, a second antenna unit 6b, a central grounding body 7, a first side grounding body 8a and a second side grounding body 8b. The first antenna unit 6a, the second antenna unit 6b, the central grounding body 7, the first side grounding body 8a and the second side grounding body 8b are disposed on one surface of the substrate 5. The first antenna unit 6a is disposed on the first antenna unit 6a. Central ground Between the body 7 and the first grounding body 8a, and forming a second spacing to feed the signal to the first antenna unit 6a by the coplanar waveguide; the second antenna unit 6b is disposed at the central grounding body 7 And the second side grounding body 8b is formed with two spaces to feed the signal to the second antenna unit 6b by the coplanar waveguide. The first antenna unit 6a and the second antenna unit 6b are mirror-symmetrical, and the substrate 5 is substantially the same as the material of the substrate 1 of the first embodiment, and the first antenna unit 6a and the second antenna are The unit 6b is substantially the same as the material of the antenna unit 2 of the first embodiment. The central grounding body 7 is substantially the same material as the first grounding body 3 of the first embodiment. The first side grounding body 8a and the second side are The grounding body 8b is substantially the same as the material of the second grounding body 4 of the first embodiment, and will not be described herein. In this embodiment, as shown in FIG. 4, the first antenna unit 6a and the second antenna unit 6b are mirror-symmetrical with a central axis C.

Please refer to FIG. 4 again, wherein the first antenna unit 6a has a first The first feeding portion 61a and the first radiating portion 62a are substantially the same as the feeding portion 21 and the radiating portion 22 of the first embodiment, and are not described here. The first feeding portion 61a is located between the central grounding body 7 and the first side grounding body 8a; the first radiating portion 62a is connected to the first feeding portion 61a. The second antenna unit 6b has a second feeding portion 61b and a second radiating portion 62b, and the second feeding portion 61b, the second radiating portion 62b, and the first feeding portion 61a of the first antenna unit 6a. The structure of a radiating portion 62a is mirror-symmetrical along the central axis C. The second feeding portion 61b is located between the central grounding body 7 and the second grounding body 8b. The second radiating portion 62b is connected to the second feeding portion. 61b.

Please refer to FIG. 4 again, wherein the central grounding body 7 and the first day mentioned above The first feeding portion 61a of the wire unit 6a has a first pitch G1', and the first grounding body 7 and the second feeding portion 61b of the second antenna unit 6b also have the first pitch G1'. The central grounding body 7 has a first hollow portion 71a and a second hollow portion 71b. The first hollow portion 71a has substantially the same structure as the hollow portion 31 of the first embodiment, and is not described herein. A hollow portion 71a and the radiating portion 62a of the first antenna unit 6a are mirrored along an axis of symmetry Xa Symmetrical; the second hollow portion 71b and the radiating portion 62b of the second antenna unit 6b are mirror-symmetrical along an axis of symmetry Xb, and the first hollow portion 71a and the second hollow portion 71b are mirror-symmetrical along a central axis C. . In this embodiment, as shown in FIG. 4, the structure of the second hollow portion 71b and the first hollow portion 71a is mirror-symmetrical along the central axis C. In addition, the central grounding body 7 can also be provided with a slot 72 which is mirror-symmetrical along the central axis C for enhancing the isolation between the first antenna unit 6a and the second antenna unit 6b. Degrees, such as: Improve the depth of the S21 characteristic curve to increase the bandwidth of the isolation. In this embodiment, the slot 72 has a connecting section hole 721 and two side section holes 722. The connecting section hole 721 communicates with the two side section holes 722, and the two side section holes 722 are respectively located at the center. The two sides of the axis C are preferably parallel to the central axis C, wherein the length of the two side holes 722 is 6.5 mm, and the length of the connecting hole 721 is 18 to 20 mm. The segment hole 721 and the two side segment holes 722 have a width of 0.5 mm, and the distance between the two side segment holes 722 and the first hollow portion 71a and the second hollow portion 71b is 1 to 1.5 mm, but not limited thereto.

Please refer to FIG. 4 again, wherein the first side grounding body 8a and the first side are The first feeding portion 61a of the antenna unit 6a has a second spacing G2', and the first side grounding body 8a has a third spacing G3' between the first radiating portion 62a of the first antenna unit 6a. The third pitch G3' is greater than the second pitch G2'. The second grounding body 8b and the second feeding portion 61b of the second antenna unit 6b also have the second spacing G2', and the second grounding body 8b and the second antenna unit 6b are second. The third portion G3' is also provided between the radiation portions 62b. In this embodiment, the distance of the second pitch G2' is the same as the first pitch G1', and the third pitch G3' may be 3.5 mm, but not limited thereto.

Please refer to FIG. 5, which is a reflection of the second embodiment of the planar antenna of the present invention. A plot of the coefficient versus frequency response. The frequency range of the S11 parameter of the second embodiment of the present invention is less than -10 dB, which is about 4 to 9 GHz, that is, the reflection coefficient of the first antenna unit and the second antenna unit in the frequency range of 4 to 9 GHz. The values are all below -10dB, so The first antenna unit and the second antenna unit of the embodiment all have the effect of good reflection coefficient.

Please refer to FIG. 6, which is the isolation of the second embodiment of the planar antenna of the present invention. A graph of the relationship between degrees and frequency response. among them. It is understood by those skilled in the art that the S21 parameter represents the isolation between the antenna elements. The smaller the value of the isolation, the better the isolation between the antenna elements, and the design parameters of the general antenna are mostly - 15dB is the benchmark with good isolation. As shown in FIG. 6, the frequency range of the S21 parameter of the present embodiment lower than -16 dB is 3 to 9 GHz, that is, more than 90% of the power in the frequency range of 3 to 9 GHz can be received, and, in the second embodiment of the present embodiment, One of the antenna elements of the line unit has less energy to be received by the other antenna unit, that is, the isolation of the two antenna elements is good.

The main features of the above embodiment of the planar antenna of the present invention by the technical means disclosed above The antenna unit is disposed on the surface of one of the substrates, and the first grounding body and the second grounding body are disposed between the first grounding body and the second grounding body, and the antenna unit has The feeding portion and the radiating portion are located between the first grounding body and the second grounding body; the first edge of the radiating portion is connected to the feeding portion, and the second edge of the radiating portion is opposite to the first edge, A matching edge of the radiating portion (eg, an arc or a rectangular edge, etc.) is coupled to the second edge such that the length of the second edge is less than the length of the first edge, so that the antenna unit can transmit and receive radio waves of a wide frequency band. By analogy, the present invention can also increase the number of antenna elements to form a multi-input and output antenna, so that each antenna unit can receive radio waves of a wide frequency band. Therefore, radio waves of a wide frequency band can be transmitted and received without setting an isolation component, and the reflection coefficient of the antenna unit can be reduced; when a plurality of antenna elements constitute a multi-input and output antenna, the difference between different antenna units can also be improved. The isolation, as well as, reduces the reflection coefficient of the antenna element. Moreover, the present invention can also be integrated with existing printed circuit board processes and reduce the overall area for use in handheld devices or other smaller volume devices.

The above embodiment of the planar antenna of the present invention, in addition to being applicable to broadband operation, can also be reduced Small footprint, and no need to provide isolation components, thus achieving "increasing isolation between antenna elements", "Reducing the reflection coefficient of the antenna unit", "can be directly integrated into the existing printed circuit board process" and "reducing the overall volume".

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

1‧‧‧Substrate

2‧‧‧Antenna unit

3‧‧‧First grounding body

4‧‧‧Second grounding body

Claims (22)

A planar antenna includes: a substrate; an antenna unit having a feeding portion and a radiating portion, the radiating portion is connected to the feeding portion; a first grounding body having a hollow portion, the hollow portion and the radiating portion The extending direction of the feeding portion is mirror-symmetrical; and a second grounding body is opposite to the radiating portion; wherein the antenna unit, the first grounding body and the second grounding system are disposed on the same surface of the substrate, the feeding portion The first grounding body and the second grounding body are disposed between the first grounding body and the second grounding body. The planar antenna of claim 1, wherein the radiating portion has a first edge, a second edge and a matching edge, the first edge connecting the feeding portion, the second edge and the first edge In contrast, the matching edge joins the second edge, the length of the second edge being less than the length of the first edge. The planar antenna of claim 2, wherein the matching edge is a curved edge. The planar antenna of claim 3, wherein the curved edge is a quarter of a circumference of a circle. The planar antenna of claim 4, wherein the circle has a radius of 6.5 to 7 mm. The planar antenna according to claim 1, wherein the hollow portion has a third edge, a fourth edge and a mating edge, and an opening is formed between the third edge and the mating edge toward the radiating portion. The fourth edge is opposite the third edge, the mating edge is connected to the fourth edge, and the length of the fourth edge is less than the length of the third edge. The planar antenna of claim 6, wherein the mating edge is a curved edge. The planar antenna of claim 7, wherein the curved edge is a quarter of a circumference of a circle. A planar antenna according to claim 8 wherein the radius of the circle is 6.5 to 7 mm. The planar antenna according to claim 1, wherein the first grounding body and the feeding portion have a first spacing, and the second grounding body and the feeding portion have a second spacing, the radiation There is a third spacing between the portion and the second grounding body, the third spacing being greater than the second spacing and the first spacing. A planar antenna includes: a substrate; a first antenna unit having a first feeding portion and a first radiating portion, wherein the first radiating portion is connected to the first feeding portion; and a second antenna unit has a a second feeding portion and a second radiating portion, the second radiating portion is connected to the second feeding portion; a central grounding body having a first hollow portion and a second hollow portion, the first hollow portion and the first portion The radiation portion is mirror-symmetrical along the extending direction of the first feeding portion, and the second hollow portion and the second radiating portion are mirror-symmetrical along the extending direction of the second feeding portion; a first side grounding body, and the first And the second side grounding body is opposite to the second radiating portion; wherein the first antenna unit, the second antenna unit, the central grounding body, the first side grounding body, and the first The second grounding system is disposed on the same surface of the substrate, the first feeding portion is disposed between the central grounding body and the first grounding body, and the second feeding portion is disposed on the central grounding body and the second side is grounded Between the bodies. The planar antenna according to claim 11, wherein the first hollow portion and the second hollow portion have an axis of symmetry, and the central grounding body is provided with a slot. The slots are mirror symmetrical along the axis of symmetry. The planar antenna according to claim 12, wherein the slot has a connecting section hole and two side section holes, the connecting section hole communicating with the two side section holes, wherein the two side section holes are respectively located on the axis of symmetry On both sides. The planar antenna according to claim 11 or 12, wherein the first radiating portion and the second radiating portion respectively have a first edge, a second edge and a matching edge, and the first radiating portion An edge is connected to the first feeding portion, a second edge of the first radiating portion is opposite to a first edge of the first radiating portion, and a matching edge of the first radiating portion is connected to a second edge of the first radiating portion, a first edge of the second radiating portion is connected to the second feeding portion, a second edge of the second radiating portion is opposite to a first edge of the second radiating portion, and a matching edge of the second radiating portion is connected to the second radiating portion The second edge, the length of each of the second edges is less than the length of each of the first edges. The planar antenna of claim 14, wherein each matching edge is a curved edge. The planar antenna of claim 15, wherein the curved edge is a quarter of a circumference of a circle. A planar antenna according to claim 16 wherein the radius of the circle is 6.5 to 7 mm. The planar antenna according to claim 11 or 12, wherein the first hollow portion and the second hollow portion respectively have a third edge, a fourth edge and a mating edge, and the first hollow portion An opening is formed between the three edges and the mating edge of the first hollow portion toward the first radiating portion, and a fourth edge of the first hollow portion is opposite to a third edge of the first hollow portion, the first hollow portion The mating edge is connected to the fourth edge of the first hollow portion, and another opening is formed between the third edge of the second hollow portion and the mating edge of the second hollow portion toward the second radiating portion, the second hollow portion Fourth edge and the The third edge of the second hollow portion is opposite, and the mating edge of the second hollow portion is connected to the fourth edge of the second hollow portion, and the length of each fourth edge is smaller than the length of each third edge. A planar antenna according to claim 18, wherein each of the mating edges is a curved edge. The planar antenna of claim 19, wherein the curved edge is a quarter of a circumference of a circle. A planar antenna according to claim 20, wherein the circle has a radius of 6.5 to 7 mm. The planar antenna according to claim 11 or 12, wherein the central grounding body and the first feeding portion have a first spacing, and the first grounding body and the second feeding portion have the first a second spacing between the first grounding body and the first feeding portion, the second grounding body and the second feeding portion having the second spacing, the first side grounding body and the The first radiating portion has a third spacing therebetween, and the second side grounding body and the second radiating portion have the third spacing, the third spacing being greater than the second spacing and the first spacing.