TW201931678A - Thin type antenna structure - Google Patents

Abstract

A thin type antenna structure adapted for integrating multiple communication bands is provided. The antenna structure includes high and low band slotted antenna units, high and low band strip feeding units, and high and low pass filter circuits. Each of high and low band slotted antenna units includes +45/-45 degrees orthogonal polarized slotted bow-tie antennas, and the corresponding strip feeding units are coupled feeding to two ends of the slotted bow-tie antennas. The high and low pass filter circuits are disposed between high and low band feeding unit. Accordingly, a MIMO antenna structure with high and low bands are formed, and the antenna structure can be attached on windows or the tops of the railed vehicle, to provides Internet connection service for communication apparatuses on the railed vehicle.

Description

Thin antenna structure

The present invention relates to an antenna technology, and more particularly to a thin antenna structure.

With the rapid development of mobile networks, various mass transits (such as buses, MRTs, railway vehicles, etc.) are gradually combining networking functions. The backhaul transmission of the Wi-Fi networking service on the existing railway vehicles is implemented through the fourth generation (4G) mobile communication router (Router). Most of the radio frequency (RF) antennas on the cabin equipment use an omnidirectional external antenna with a propeller type appearance. The antennas need to be separated by space diversity, and the overall construction space cannot be reduced.

On the other hand, in order to increase the transmission speed, most communication technologies are gradually combining multiple input multiple output (MIMO) antenna technology. However, the existing slot antenna architecture is still biased towards single antenna system applications. If the MIMO antenna system is implemented, the prior art usually uses multiple sets of slot antennas and staggers in a spatial diversity manner, but greatly increases the design complexity and the space occupied by the antenna body.

In addition, some prior art techniques utilize coupling elements in close proximity to the slot antenna or using multiple sets of slot units to achieve a wider resonant frequency band. However, since such design architecture applications are mostly handheld terminals, most of the operating band requirements are based only on -6dB return loss. From the point of view of energy loss, the -6dB return loss means that 25% of the energy is still reflected back to the system end, and the energy cannot be completely transmitted to the antenna end. The architecture needs to be optimized and improved.

In view of this, the present invention provides a thin antenna structure suitable for loading in any vehicle and capable of realizing a MIMO antenna system, and having better energy loss performance.

The thin antenna structure of the present invention comprises a dielectric substrate, a first slot antenna unit, a first feed end, a second feed end, a first feed unit, and a second feed unit. The dielectric substrate includes a body, a metal surface on a surface layer of the body, and a feed surface on a lower surface of the body. The first slot antenna unit is located on the metal surface and includes a first bow-tie type slot and a second bow tie type slot. The central axis of the second bow tie type slot is orthogonal to the central axis of the first bow tie type slot, and the center points of the first and second bow tie type slots overlap. The first feeding unit is located at the feeding surface and includes a first head feeding member and two first tail feeding members. One end of the first feedthrough is coupled to the first feed end. The two first tail feed members are respectively extended from the first head feed member to the two ends of the first bow tie type slot. The second feeding unit is located on the feeding surface and includes a second head feeding member and two second tail feeding members. One end of the second feedthrough is connected to the second feed end. The two second tail feed members are respectively extended from the second head feed member to the two ends of the second bow tie type slot.

In an embodiment of the invention, the body of the dielectric substrate has a side edge, and the angle between the side edge and the vertical line of the first bow-tie type slot is +45 degrees, and the side edge and the second bow tie type The angle between the vertical lines in the slot is -45 degrees.

In an embodiment of the invention, the other end of the first head feeding member is perpendicular to the vertical line of the first bow-tie type slot, and the other end of the second head feeding member is perpendicular to the vertical line of the second bow-tie type slot. .

In an embodiment of the invention, each of the first tail feedthroughs includes a first front extension, and the first front extensions of the two first tail feedthroughs are parallel to the vertical line of the first bowtie type slot Forming a T-junction with the first head feedthrough.

In an embodiment of the invention, each of the second tail feedthroughs includes a second front extension, and the second front extensions of the two first tail feedthroughs are parallel to the vertical line of the second bow tie slot Forming a T-shaped engagement with the second feedthrough.

In an embodiment of the invention, one of the second tail feedthroughs includes a first rear extension extending vertically from one end of the second front extension, and a second rear extension extending from the first rear extension. The extension and the microstrip metal piece have two ends connected to the first and second rear extensions, and the microstrip metal piece is located below the second tail feed piece, so that the first feeding unit and the second feeding unit do not contact.

In an embodiment of the invention, the first feeding unit excites energy to the two ends of the first bow-tie slot by coupling feeding, and the second feeding unit excites energy to the second by coupling feeding. The bow tie type has two ends.

In an embodiment of the invention, the thin antenna structure further includes a second slot antenna unit, a third feed unit, and a fourth feed unit. The second trough antenna unit is located on the metal surface and spaced apart from the first trough antenna, and includes a third bowtie type slot and a fourth bow tie type slot. The central axis of the fourth bow tie slot is orthogonal to the central axis of the third bow tie slot, and the center points of the third and fourth bow tie slots overlap. The third feeding unit is located on the feeding surface and includes a third head feeding member and two third tail feeding members. One end of the third feedthrough is connected to the first feed end. The two third tail feed members are respectively extended from the third feed member to the two ends of the third bow tie slot. The fourth feeding unit is located at the feeding surface and includes a fourth head feeding member and two fourth tail feeding members. One end of the fourth feedthrough is connected to the second feed end. The second and fourth tail feed members are respectively extended from the fourth head feed member to the two ends of the fourth bow tie type slot.

In an embodiment of the invention, the thin antenna structure further includes first and second high pass and low pass filter circuits. The first high pass and low pass filter circuit is disposed between the first feed unit and the third feed unit. The second high pass and low pass filter circuit is disposed between the first feed unit and the fourth feed unit.

In an embodiment of the invention, the first or second high-pass and low-pass filter circuit includes a low-pass capacitor, a low-pass inductor connected in series with the low-pass capacitor, a high-pass inductor, a high-pass capacitor connected in series with the high-pass inductor, and a high-pass parallel capacitance. The low-pass capacitor and the inductor are used to connect the first or second feed unit, and the high-pass inductor, capacitor and shunt capacitor are used to connect the third or fourth feed unit.

Based on the above, the embodiment of the present invention implements the polarization diversity method and implements the center point orthogonal polarization slot antenna method, which can effectively reduce the space required by the antenna and help improve the isolation of the multi-antenna system. In order to avoid the influence of the feeding 埠 contact with each other, the two-T-Junction microstrip line coupling is fed to both ends of the bow-tie slot. The overall structure is simple and symmetrical, so it is easy to ensure polarization purity. To reduce antenna correlation. In addition, the high and low frequency orthogonal slot antennas are independently designed and integrated with high-pass and low-pass filter circuits to reduce the impedance characteristics of the high and low frequency bands, which can meet the -10dB return loss specification in the operating band of 4G 900MHz/1800MHz/2600MHz. Thereby, the antenna cover can be integrated and mounted on the roof of the railway vehicle. Or, by a thin appearance, it is installed on the information board at either side of the railway vehicle or at the window.

The above described features and advantages of the invention will be apparent from the following description.

1A and 1B are schematic views of a thin antenna structure 1 in accordance with a first embodiment of the present invention. 1A and 1B, the thin antenna structure 1 includes a dielectric substrate 11, a slot antenna unit 122, feed terminals 161, 162, and feed units 131, 132.

The dielectric substrate 11 includes a body, a metal surface 12 on the surface of the body (shown in FIG. 1B), and a feed surface 13 on the lower surface of the body (shown in FIG. 1A).

The slot antenna unit 122 is located on the metal face 12 and includes Bow-tie shaped slots 1221, 1222 to increase the operating bandwidth. The bow tie slot 1221 is formed by two opposite and symmetrical triangles formed by the slot sides 1221A~1221C and 1221D~1221F, and the bow tie slot 1222 is formed by the slot sides 1222A~1221C and 1222D~1222F. Consisting of relatively symmetrical triangles. The two bow-tie slots 1221, 1222 are substantially equal in shape, and wherein the vertical lines (perpendicularly perpendicular to the normals of the opposite slot sides 1221B and 1221E, 1222B and 122E) are orthogonal to the center of the bow-tie slots 1221, 1222 Point and overlap to form a cross shape. In addition, the angle between the vertical line of the bow-tie slot 1221 and the bottom side of the body of the dielectric substrate 11 (the bottommost side shown in FIG. 1A, parallel to the ground plane) is +45 degrees, and the bow-tie slot 1222 The middle vertical line is -45 degrees between the bottom side of the body of the dielectric substrate 11.

The feed ends 161, 162 are respectively connected to radio frequency (RF) coaxial lines, which are located substantially opposite to each other on the metal surface 12.

The feed units 131, 132 are located on the feed face 13 and are implemented by the microstrip line. The feed unit 131 includes a head feed member 1313 and two tail feed members 1311, 1312. One end of the head feedthrough 1313 is connected to the feed end 161, and the other end thereof is perpendicular to the vertical line in the bow tie slot 1221. The tail feedthrough 1311 includes a front extension 1311A perpendicular to the other end of the head feedthrough 1313 and a rear extension 1311B extending perpendicularly to the front extension 1311A. The tail feedthrough 1311 spans the slot edge 1221A of the bowtie slot 1221 and is partially overlapped with the bowtie slot 1221. The tail feedthrough 1312 includes a front extension 1312A perpendicular to the other end of the head feedthrough 1313, a rear extension 1312B extending vertically from one end of the front extension 1312A, and a rear extension 1312C extending from the extension of the rear extension 1312B. And the microstrip metal piece 1312D has two ends connected by a via hole 152 to the rear extension portions 1312B, 1312C (partially enlarged by AA as shown in FIG. 1C). The tail feed member 1312 spans the slot edge 1221D of the bow tie slot 1221 and is partially overlapped with the bow tie slot 1221. Further, the front extensions 1311A, 1312A are parallel to the vertical line in the bowtie type slot 1221 and form a T-junction with the head feedthrough 1313. In other words, the feed unit 131 is composed of a one-two-two-junction feed-in network. The feed unit 131 has a line width of approximately 50 ohms characteristic impedance, and utilizes a tapered transmission line to a 100 ohm characteristic impedance. Finally, the rear extensions 1311B and 1312B are further connected in parallel to form a 50 ohm characteristic impedance, so that the current is self-contained. After the feeding end 161 is fed in, it is transmitted through the feeding unit 131, and energy is applied to both ends of the bow-tie type slot 1221 by coupling feeding.

On the other hand, the feed unit 132 includes a head feed member 1323 and two tail feed members 1321, 1322. One end of the head feedthrough 1323 is coupled to the feed end 162 and the other end thereof is perpendicular to the vertical line in the bow tie slot 1222. The tail feedthrough 1321 includes a front extension 1321A that is perpendicular to the other end of the head feed 1323, and a rear extension 1321B that extends perpendicularly to the front extension 1321A. The position of the rear extension portion 1311B overlaps with the bowtie type slot 1222. The tail feedthrough 1312 includes a front extension 1322A that is perpendicular to the other end of the head feedthrough 1323, and a rear extension 1322B that extends perpendicularly from one end of the front extension 1312A. In addition, the front extensions 1321A, 1322A are parallel to the vertical line in the bowtie slot 1222 and form a T-junction with the head feedthrough 1323. In other words, the feeding unit 131 is also composed of a one-two T-type joint feeding network, and the current is fed from the feeding end 162, transmitted through the feeding unit 132, and the energy is sent by the coupling feeding method. At both ends of the bow tie slot 1222. It should be noted that, referring to FIG. 1C, the junction of the feeding units 131, 132 is partially broken through the feed member 1312 of the feeding portion 131, and the broken portion is continued with the microstrip metal piece 1312D to form a complete transmission path. Thereby, the two T-junction microstrip line contacts of the feeding units 131, 132 are avoided (ie, the feeding units 131, 132 are not in contact) to affect the antenna performance. The two T-junctions formed by the feed units 131, 132 are arranged orthogonally.

In addition, the shape and size of the feeding units 131, 132 are also factors affecting the performance of the antenna (for example, the two distances D1, D2 shown in FIG. 1A are the distance between the two rear extensions 1321B, 1322B, and the rear extension 1321B, respectively. The feeding unit 132 is taken as an example, and the feeding unit 131 can be referred to because of the shape symmetry. The preferred embodiment can refer to the range of the table (1), but the value may still be adjusted due to the change of part of the thin antenna structure 1. : Table 1)

In order to integrate the multi-band, the thin antenna structure 1 of the first embodiment can be changed. 2A is a schematic view of a thin antenna structure 2 in accordance with a second embodiment of the present invention. The thin antenna structure 2 includes a dielectric substrate 21, slot antenna units 221, 222, high frequency and low frequency filter circuits 241, 242, feed terminals 261, 262, and feed units 231, 232, 233, 234.

The dielectric substrate 21 includes a body, a metal surface 22, and a feed surface 23. For a detailed description, reference may be made to the description of the dielectric substrate 11 with reference to FIGS. 1A and 1B, and details are not described herein again.

The slot antenna elements 221, 222 are located on the metal face 22 and include bowtie slots 2211, 2211, 2221, 2222, respectively. The slot antenna elements 221, 222 have substantially the same shape and structure, and the detailed description thereof can be referred to the slot antenna unit 122 in FIGS. 1A and 1B, and details are not described herein again. It should be noted that the slot antenna units 221, 222 can be implemented in the high frequency band and the low frequency band respectively, in order to comply with the operating band of the Long Term Evolution (LTE) 900 MHz/1800 MHz/2600 MHz, and realize the multi-band antenna structure.

The feed ends 261, 262 are respectively connected to radio frequency (RF) coaxial lines, which are located substantially opposite to each other on the metal surface 22.

The feed units 231, 232, 233, 234 are located on the feed surface 23 and are implemented by the microstrip line. For detailed description, reference may be made to the description of the feed units 131, 132 with reference to FIGS. 1A and 1B, and details are not described herein. The current is transmitted through the feeding units 231, 232, 233, 234 in a one-two manner (T-junction), and the energy is respectively sent to the ends of the bow-tie slots 2221, 2222, 2211, 2212 by the coupling feeding method. Referring to the partial enlargement of BB shown in FIG. 2B, similarly, the junction of the feeding units 231, 232 is partially disconnected through the feeding unit 231 and connected through the via hole 252 through the microstrip metal piece 231A, so that the feeding units 231, 232 are not Contact; please refer to the partial amplification of CC shown in FIG. 2C. Similarly, at the junction of the feeding units 233, 234, the feeding unit 234 is partially disconnected and connected by the microstrip metal piece 234A through the through hole 251, so that the feeding unit 233, 234 No contact, so it will not affect the antenna performance of high and low frequency bands.

Another difference from the first embodiment is that the thin antenna structure 2 is provided with high-pass and low-pass filter circuits 241, 242 between the feed units 231 and 233 and between the feed units 232 and 234, respectively. Please refer to FIG. 3 for a schematic diagram and an equivalent circuit of the high pass and low pass filter circuits 241, 242. The high-pass and low-pass filter circuit 241 is a radio frequency circuit composed of five passive components, including: a low-pass capacitor 2411, a low-pass inductor 2412 connected in series with the low-pass capacitor 2411, a high-pass shunt capacitor 2413, and a high-pass shunt capacitor 2413 in parallel. The high-pass inductor 2414 and the high-pass capacitor 2415 in series with the high-pass inductor 2414; the low-pass capacitor 2411 and the low-pass inductor 2412 are used to connect the low-band microstrip line feed portion 231, and the high-pass shunt capacitor 2413, the high-pass inductor 2414, and the high-pass capacitor The 1415 is used to connect the microstrip feed unit 232 of the high frequency band. The high-pass and low-pass filter circuit 242 is also a radio frequency circuit composed of five passive components, including: a low-pass capacitor 2421, a low-pass inductor 2422 connected in series with the low-pass capacitor 2421, a high-pass shunt capacitor 2423, and a high-pass shunt capacitor 2423. The high-pass inductor 2424 and the high-pass capacitor 2425 connected in series with the high-pass inductor 2414; the low-pass capacitor 2421 and the low-pass inductor 2422 are used to connect the low-band microstrip line feed unit 232, and the high-pass shunt capacitor 2423, the high-pass inductor 2424, and The high pass capacitor 2425 is used to connect the microstrip feed portion 234 of the high frequency band. The equivalent circuit of the two high-pass and low-pass filter circuits 241, 242 is shown in the circuit diagram shown on the left, and the related passive component values include: the value of the low-pass capacitor C _low is between 1 and 3 pF, and the value of the low-pass inductor L _low is between 12 ~15nH, high-pass shunt capacitor C _par value is between 0.5~2pF, high-pass inductor L _high is between 3~5nH, and high-pass capacitor C _high is between 1~3pF, and Qualcomm can be optimized by component value adjustment The frequency response is with the low pass filter circuits 241, 242.

Since the high-band signal can be observed on the low-band path, there is a higher impedance value on the path; on the other hand, the low-band signal can be observed to have a higher impedance value on the path in the high-band path, so the level is high. In the integration of the frequency bands, the current signals will only be distributed to the respective transmission line paths without causing mutual interference. 4 is an electrical analysis result of the high-pass and low-pass filter circuits 241, 242. It can be observed that the insertion loss (Insert Loss) generated by the low-pass and high-pass circuits is about 1 to 1.5 dB, and the reflection coefficient (Reflection Coefficient) after integration is observed. Can be less than -10dB, can meet the circuit design needs.

Figure 5 is a diagram showing the relationship between the reflection coefficient of the antenna of the multi-band antenna structure and the frequency. The operating band defined by the reflection coefficient of about -10 dB can cover LTE 900 MHz/1800 MHz/2600 MHz, and the isolation of the low-band and high-band antennas can be less than 13 dB and less than 20 dB. The multi-band antenna structure is a 2Tx-2Rx multi-antenna system, so it can be applied to a Multiple Input Multiple Output (MIMO) communication system. 6A, 6B and 6C are the relationship between the field type and the measurement angle of the 45-degree and 135-degree sections of the multi-band antenna structure at 900MHz, 1800MHz and 2600MHz. It can be observed to operate at 900MHz, 1800MHz and 2600MHz. At the frequency, the antenna gain values at the 45 degree and 135 degree sections are between 2 and 3 dBi.

The thin antenna architecture 1, 2 of the embodiment of the present invention can be used to connect 4G router devices, and the general 4G router device can be used as a transmission medium for a Wi-Fi backhaul network (Backhaul) in a railway vehicle. Therefore, enhancing the RF performance of the 4G router can improve the transmission quality of the ground base station, and further optimize the transmission performance of the Wi-Fi equipment backhaul network.

As shown in FIG. 7, the embodiment of the present invention can further integrate the antenna cover and install it in the roof space of the railway vehicle T. The thin antenna structure 2 serves as an antenna module of the 4G router R, and is provided by the Wi-Fi sharer W. The service, and the mobile communication signal is transmitted to the ground base station as a Wi-Fi backhaul network. For non-tunnel sections, the antenna is not easy to be shielded when installed in the roof space. The vehicle-to-ground transmission path is mainly based on direct-view propagation to ensure the quality of the 4G router equipment in the vehicle under each service cell. In this way, the user can connect the networked device to the Wi-Fi sharer W and connect to the Internet via the 4G router R.

In addition, referring to FIG. 8 , the thin antenna structure 1 and 2 of the embodiment of the present invention have a thin appearance and can be installed at the information board or the window side of the east and west sides of the railway vehicle T2, and pass through a splitter and splitter (corresponding to the thin type) The T-junction structure of the antenna architecture 1, 2) combines 2Tx-2Rx MIMO antenna elements on both sides of the east and west (corresponding to the two slot antenna elements 221, 222 of the thin antenna architecture 2) in different polarization arrangements. In this way, for tunnel segment communication, the wave signal can be extended to the east and west sides, and the bleeder cable placed on the east and west sides of the tunnel segment can achieve better transmission efficiency, and the transmission quality of the railway vehicle T2 entering the tunnel area from the non-tunnel segment is consistent. Sex.

Generally speaking, if the antenna is placed at the roof position, when entering the tunnel area, since the bleeder cable in the tunnel area is adjacent to the vehicle body, there is a large vehicle body diffraction loss for the wireless transmission of the roof antenna and the bleeder cable. Therefore, if different antenna deployment modes (the roof (Fig. 7) and the window edge (Fig. 8)) can be performed simultaneously for the two fields, the antenna switching selection in different communication environments can be achieved, and the Wi-Fi device backhaul can be improved in the vehicle compartment. The quality of network transmission is quite helpful. Under the condition of greatly improving the bottleneck of vehicle-to-ground transmission, it is sure to effectively improve the Wi-Fi networking quality and quality user experience of passengers in the cabin.

In summary, the embodiment of the present invention utilizes an orthogonally polarized slot antenna to effectively reduce the space required by the antenna and to improve the isolation of the multi-antenna system. The one-two T-Junction microstrip line is coupled to both ends of the bowtie type slot, and the overall structure is simple and symmetrical, which ensures polarization purity and helps to reduce antenna correlation. In the embodiment of the invention, the high and low frequency orthogonal slot antennas are independently designed, and the high-pass and low-pass filter circuit units are integrated to reduce the impedance characteristics of the high and low frequency bands, and can satisfy the -10 dB return loss in the operating band of LTE 900 MHz/1800 MHz/2600 MHz. specification. The antenna architecture of the present invention can be used to connect 4G router devices, and the RF performance of the 4G router can be enhanced to improve the transmission quality of the ground base station. In addition, the embodiment of the present invention has a thin appearance and can be further integrated into a transportation vehicle such as a railway vehicle or a bus (a roof space or a window design).

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

1, 2‧‧‧ Thin Antenna Architecture

11, 21‧‧‧ dielectric substrate

12, 22‧‧‧Metal surface

13, 23‧‧‧Feeding

122, 221, 222‧‧‧ slot antenna unit

1221, 1222, 2211, 2212, 2221, 2222‧‧‧ bow tie slots

1221A~1221C, 1221D~1221F, 1222A~1221C, 1222D~1222F‧‧‧ slot side

131, 132, 231, 232, 233, 234‧‧‧ feed units

1331, 1312, 1321, 1322‧‧‧ tail feeds

1311A, 1312A, 1321A, 1322A‧‧‧ Front extension

1311B, 1312B, 1312C, 1321B, 1322B‧‧‧ rear extension

1312D, 231A, 234A‧‧‧ microstrip metal sheet

1313, 1323‧‧‧ head feeds

152, 251, 252‧‧‧ vias

161, 162, 261, 262‧‧ ‧ feed end

241, 242‧‧‧ high-pass and low-pass filter circuits

2411, 2421, C _low ‧‧‧ low-pass capacitor

2412, 2422, L _low ‧‧‧ low pass inductor

2413, 2423, C _par ‧‧‧ high-pass shunt capacitor

2414, 2424, L _high ‧‧‧ high pass inductor

2415, 2425, C _high ‧‧‧ high pass capacitor

D1, D2‧‧‧ distance

R‧‧‧4G router

W‧‧ Wi-Fi sharing device

T, T2‧‧‧ railway vehicles

1A-1B are schematic views of a thin antenna structure in accordance with a first embodiment of the present invention. Figure 1C is a partial enlarged view of A-A of Figures 1A-1B. 2A is a schematic view showing the structure of a thin antenna according to a second embodiment of the present invention. Fig. 2B is a partial enlarged view of B-B of Fig. 2A. Figure 2C is a partial enlarged view of C-C of Figure 2A. 3 is a schematic diagram and an equivalent circuit of a high pass and low pass filter circuit in accordance with a second embodiment of the present invention. 4 is a graph showing the reflection loss of the high pass and low pass filter circuits of the second embodiment of the present invention. Figure 5 is a frequency response diagram of a second embodiment of the present invention. 6A-6C are plan views of a planar radiation pattern of a second embodiment of the present invention. Fig. 7 is a diagram illustrating an antenna disposed on a roof side of a railway vehicle. Figure 8 is another illustration of an antenna disposed inside a railway vehicle.

Claims (10)

A thin antenna structure comprising: a dielectric substrate, comprising: a body; a metal surface on the surface of the body; and a feed surface on the lower surface of the body; a first slot antenna unit located on the metal surface, and The method includes: a first bow-tie type slot; and a second bow-tie type slot, wherein an axis is orthogonal to an axis of the first bow-tie type slot, and the first and second bow-tie types a center point of the slot overlaps; a first feed end; a second feed end; a first feed unit located on the feed surface, and comprising: a first head feedthrough, one end connected to the first a feeding end; two first tail feeding members respectively extending from the first head feeding member to the two ends of the first bowing type slot; and a second feeding unit located at the feeding surface, and comprising: a second feeding member, one end connected to the second feeding end; and two second tail feeding members respectively extending from the second head feeding member to the two ends of the second bowing type slot. The thin antenna structure of claim 1, wherein the body of the dielectric substrate has a side edge, and the angle between the side edge and the vertical line of the first bow tie type slot is +45 degrees, and the angle is The angle between the side edge and the perpendicular line in the second bow tie type slot is -45 degrees. The thin antenna structure according to claim 1, wherein the other end of the first head feeding member is perpendicular to a vertical line of the first bow-tie type slot, and the other end of the second head feeding member is opposite to the first The vertical line of the two bow-tie slots is vertical. The thin antenna structure of claim 3, wherein each of the first tail feedthroughs includes a first front extension, and the first front extension of the two first tail feedthroughs and the first The vertical line of the bowtie type slot is parallel and forms a T-junction with the first head feedthrough. The thin antenna structure of claim 3, wherein each second tail feedthrough includes a second front extension, and the second front extension of the two first tail feeds and the second The vertical line of the bow tie slot is parallel and forms a T-shaped engagement with the second head feedthrough. The thin antenna structure according to claim 5, wherein the second tail feed member comprises a first rear extension portion extending perpendicularly from one end of the second front extension portion, and a second rear extension portion being The first rear extension extends in a direction, and a microstrip metal sheet has two ends connected to the first and second rear extensions, and the microstrip metal piece is located under the second tail feed member, so that the The first feeding unit is not in contact with the second feeding unit. The thin antenna structure of claim 1, wherein the first feeding unit excites energy to the two ends of the first bow-tie slot by coupling feeding, and the second feeding unit is coupled by a feed. The input mode excites energy to both ends of the second bowtie type slot. The thin antenna structure of claim 1, further comprising: a second slot antenna unit located on the metal surface, spaced apart from the first slot antenna unit, and including: a third a bow tie type slot; and a fourth bow tie type slot, wherein an axis is orthogonal to an axis of the third bow tie type slot, and a center point of the third and the fourth bow tie type slot overlaps; a feeding unit, located at the feeding surface, and comprising: a third feeding member, one end connected to the first feeding end; and a second tail feeding member respectively extended by the third head feeding member And a fourth feeding unit located at the feeding surface, and comprising: a fourth feeding member, one end connected to the second feeding end; and the second fourth feeding member And extending from the fourth head feeding member to the two ends of the fourth bow-tie type slot. The thin antenna structure of claim 8, further comprising: a first high pass and low pass filter circuit disposed between the first feed unit and the third feed unit; and a second high pass And a low pass filter circuit disposed between the second feed unit and the fourth feed unit. The thin antenna structure of claim 9, wherein the first or second high-pass and low-pass filter circuit comprises a low-pass capacitor, a low-pass inductor and the low-pass capacitor in series, a high-pass inductor, and a high-pass The capacitor is connected in series with the high-pass inductor and a high-pass shunt capacitor, wherein the low-pass capacitor and the low-pass inductor are used to connect the first or the second feed unit, and the high-pass inductor, the high-pass capacitor, and the high-pass capacitor are connected in parallel A capacitor is used to connect the third or the fourth feeding unit.