A dual circularly polarized leaky-wave antenna based on substrate integrated waveguide

Abstract

The application belongs to the technical field of antennas and discloses a double circular polarization leaky-wave antenna based on a substrate integrated waveguide, which comprises a feeding structure and a radiating structure; the feeding structure is symmetrically arranged at two ends of the radiating structure, and both the feeding structure and the radiating structure are substrate integrated waveguides; the feeding structure is used for converting received external electromagnetic energy into guided electromagnetic waves and has the characteristic of widening impedance; wherein a gradually changing coplanar waveguide transmission line is designed in the feeding structure; the radiating structure is used for converting the guided electromagnetic waves transmitted by the feeding structure into circular polarization electromagnetic waves in free space; wherein a grid window leaky-wave structure is designed in the radiating structure; by combining the leaky-wave antenna and the substrate integrated waveguide technology, the gradually changing coplanar waveguide transmission line is designed on the feeding structure, the grid window leaky-wave structure is designed along the radiating structure, the millimeter wave working frequency band requirement is realized, and the characteristics of wide axial ratio bandwidth, low sidelobe, large scanning range, low profile and low cost are achieved.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and specifically relates to a dual-circularly polarized leaky wave antenna based on a substrate integrated waveguide. Background Technology

[0002] Leaky-wave antennas (LWA) are a type of traveling-wave antenna, characterized by wide bandwidth, beam scanning capability, ease of integration, and low cost. With the development of modern wireless communication technology, the millimeter-wave band has received increasing attention due to its advantages such as high communication capacity and strong anti-interference capability. Millimeter-wave leaky-wave antennas combine the above advantages and have been widely developed and applied in radar systems, 5G communication, sensing and other fields.

[0003] Millimeter-wave leaky antennas are key components in wireless communication, playing a crucial role in the entire system. With the continuous emergence of various application scenarios, wireless systems require antenna terminals to have characteristics such as wide bandwidth, anti-interference, and flexible directivity. Most existing leaky antennas are linearly polarized, which suffers from polarization mismatch and poor resistance to multipath effects, thus affecting communication quality. Circularly polarized antennas, on the other hand, have the ability to resist polarization loss and effectively suppress multipath interference, especially in mobile communication applications. Therefore, circularly polarized antennas can effectively improve the reliability and stability of the system. However, existing circularly polarized millimeter-wave leaky antennas generally suffer from technical problems such as narrow axial ratio bandwidth, narrow beam scanning range, and poor antenna anti-interference capability. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a dual circularly polarized leaky wave antenna based on a substrate integrated waveguide, in order to solve the technical problems of narrow axial ratio bandwidth, narrow beam scanning range, and poor anti-interference capability that are common in existing circularly polarized millimeter-wave leaky wave antennas.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a dual-circularly polarized leaky antenna based on a substrate integrated waveguide, comprising a feeding structure and a radiating structure; the feeding structure is symmetrically disposed at both ends of the radiating structure, and both the feeding structure and the radiating structure are substrate integrated waveguides;

[0007] The feeding structure is used to convert received external electromagnetic energy into guided electromagnetic waves and has the characteristic of broadening impedance; wherein, the feeding structure is designed with a gradually changing coplanar waveguide transmission line.

[0008] The radiation structure is used to convert the guided electromagnetic waves transmitted by the feeding structure into circularly polarized electromagnetic waves in free space; wherein, the radiation structure is designed with a grid window leakage structure.

[0009] Furthermore, the power feeding structure includes a first metal layer power feeding portion, a dielectric substrate layer power feeding portion, and a second metal layer power feeding portion stacked sequentially from top to bottom;

[0010] A coplanar waveguide transmission line is arranged along the longitudinal centerline of the first metal layer feeding section. The coplanar waveguide transmission line is a tapered coplanar waveguide transmission line. The tapered coplanar waveguide transmission line includes a straight segment and a trapezoidal tapered segment. The first end of the straight segment is the input end of the feeding structure, the second end of the straight segment is connected to the small-sized end of the trapezoidal tapered segment, and the large-sized end of the trapezoidal tapered segment is connected to the radiating structure.

[0011] Furthermore, a first metal via is provided on the first metal layer feeding portion. The first metal via is symmetrically disposed on both sides of the coplanar waveguide transmission line and uniformly distributed along the longitudinal edge of the coplanar waveguide transmission line. The first metal via penetrates the dielectric substrate layer feeding portion and is connected to the second metal layer feeding portion.

[0012] Furthermore, it also includes an input port, which is located at the end of the power supply structure and connected to the first end of the straight segment.

[0013] Furthermore, the first metal layer feed portion is printed on the upper surface of the dielectric substrate layer feed portion, and the second metal layer feed portion is printed on the lower surface of the dielectric substrate layer feed portion.

[0014] Furthermore, the radiation structure includes a first metal layer radiation portion, a dielectric substrate layer radiation portion, and a second metal layer radiation portion, which are stacked sequentially from top to bottom;

[0015] The first metal layer radiating portion includes a plurality of cells distributed sequentially along the longitudinal centerline; a grid window structure is provided on one side of the longitudinal centerline of the cell, and a row of second metal vias distributed in a straight line is provided on the other side of the longitudinal centerline of the cell.

[0016] Two rows of third metal vias with a sawtooth pattern are provided on both sides of the longitudinal center line of the cell; one row of third metal vias with a sawtooth pattern is located on the outside of the grid window structure, and the other row of third metal vias with a sawtooth pattern is located on the outside of the second metal vias with a straight line.

[0017] Furthermore, the top end of the second metal via is connected to the radiating portion of the first metal layer, and the bottom end of the second metal via penetrates the radiating portion of the dielectric substrate layer and is connected to the radiating portion of the second metal layer.

[0018] Furthermore, the top end of the third metal via is connected to the radiating portion of the first metal layer, and the bottom end of the third metal via penetrates the radiating portion of the dielectric substrate layer and is connected to the radiating portion of the second metal layer.

[0019] Furthermore, the first metal layer radiating portion is printed on the upper surface of the dielectric substrate layer radiating portion, and the second metal layer radiating portion is printed on the lower surface of the dielectric substrate layer radiating portion.

[0020] Furthermore, the grid window structure includes four groups of grid window units arranged in a rectangular array. Each group of grid window units includes two grid windows arranged in parallel, and both grid windows are parallel to the vertical center line of the cell.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention provides a dual-circularly polarized leaky antenna based on a substrate integrated waveguide. By combining leaky antenna and substrate integrated waveguide technology, a gradually tapered coplanar waveguide transmission line is designed on the feeding structure, and a grid window leaky structure is designed along the radiating structure. This achieves the requirements of the millimeter-wave operating frequency band and features a wide axial ratio, high bandwidth, low sidelobes, large scanning range, low profile, and low cost. Specifically, by adjusting the size of the grid window leaky structure, the amount of leaked electromagnetic energy can be effectively controlled, thereby meeting the requirements of a wide bandwidth, low sidelobes, and wide-angle scanning dual-circularly polarized leaky antenna for millimeter-wave communication. The dual-circularly polarized leaky antenna operates within the frequency range of 25.6 GHz to 38.3 GHz. 11 | < -10dB, relative bandwidth is 39.7%; AR < 3dB in the frequency range of 25.8GHz-37.7GHz, relative bandwidth is 37.7%, beam scanning range is 81° (-31°~50°), gain range is 13.2dBic-17.2dBic, and sidelobe level is -15.4dB at 32GHz. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the three-dimensional layered structure of the dual circularly polarized leaky antenna based on a substrate integrated waveguide described in this invention.

[0025] Figure 2 This is a planar schematic diagram of the power feeding structure in this invention;

[0026] Figure 3 This is a planar schematic diagram of the radial structure in this invention;

[0027] Figure 4 This is a planar schematic diagram of a cell in this invention;

[0028] Figure 5 This is a simulation diagram of the reflection coefficient of the dual-circularly polarized leaky antenna in this invention.

[0029] Figure 6 This is a frequency-phase relationship diagram of the cell in this invention;

[0030] Figure 7 This is the right-hand circular polarization gain pattern of the dual circular polarization leaky antenna in this invention;

[0031] Figure 8 This is a diagram showing the right-hand circular polarization axial ratio of the dual-circular polarization leaky antenna in this invention.

[0032] Figure 9 This is the left-hand circular polarization gain pattern of the dual circular polarization leaky antenna in this invention;

[0033] Figure 10 This is a diagram showing the left-hand circular polarization axial ratio of the dual-circular polarization leaky antenna in this invention.

[0034] Figure 11 The figure shows the simulation results of the gain of the dual circularly polarized leaky antenna as a function of frequency in the embodiment.

[0035] Figure 12 The figure shows the simulation results of the radiation efficiency of the dual circularly polarized leaky wave antenna in this invention as a function of frequency.

[0036] Among them, 1 is the feeding structure, 2 is the radiating structure, 3 is the first input port, 4 is the second input port; 11 is the first metal layer feeding part, 12 is the dielectric substrate layer feeding part, 13 is the second metal layer feeding part, 14 is the coplanar waveguide transmission line, 15 is the first metal via; 21 is the first metal layer radiating part, 22 is the dielectric substrate layer radiating part, 23 is the second metal layer radiating part, 24 is the cell; 241 is the grid window structure, 242 is the second metal via, 243 is the third metal via. Detailed Implementation

[0037] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0038] As attached Figure 1-4 As shown, the present invention provides a dual circularly polarized leaky antenna based on a substrate integrated waveguide, including two feeding structures 1, a radiating structure 2, a first input port 3 and a second input port 4; the two feeding structures 1 are symmetrically arranged at both ends of the radiating structure 2, the first input port 3 is arranged at the input end of one of the feeding structures, and the second input port 4 is arranged at the input end of the other feeding structure.

[0039] The first input port 3 and the second input port 4 are used to input external electromagnetic energy into the two feeding structures 1 respectively; the feeding structure 1 is used to convert the received external electromagnetic energy into guided electromagnetic waves and has the characteristic of broadening impedance; the radiation structure 2 is used to convert the guided electromagnetic waves transmitted by the feeding structure 1 into circularly polarized electromagnetic waves in free space.

[0040] The feeding structure 1 is a substrate integrated waveguide, including a first metal layer feeding portion 11, a dielectric substrate layer feeding portion 12, and a second metal layer feeding portion 13 stacked sequentially from top to bottom; the first metal layer feeding portion 11 is printed on the upper surface of the dielectric substrate layer feeding portion 12, and the second metal layer feeding portion 13 is printed on the lower surface of the dielectric substrate layer feeding portion 12; preferably, the peripheral dimensions of the first metal layer feeding portion 11 are: length L1 × width W1 = 15mm × 13mm; the peripheral dimensions of the dielectric substrate layer feeding portion 12 are: length × width × thickness = 15mm × 13mm × 0.508mm.

[0041] A coplanar waveguide transmission line 14 is arranged along the longitudinal centerline of the first metal layer feeding portion 11. The coplanar waveguide transmission line 14 is a gradient coplanar waveguide transmission line. Specifically, the gradient coplanar waveguide transmission line includes a straight segment and a trapezoidal gradient segment. The straight segment and the trapezoidal gradient segment are arranged along the longitudinal centerline of the first metal layer feeding portion 11, and are sequentially divided from the input end to the output end of the feeding structure 1. The first end of the straight segment is the input end of the feeding structure 1 and is connected to the first input port 3 or the second input port 4. The second end of the straight segment is connected to the small-sized end of the trapezoidal gradient segment, and the large-sized end of the trapezoidal gradient segment is connected to the end of the radiating structure 2. It should be noted that by arranging a gradient coplanar waveguide transmission line along the longitudinal centerline of the first metal layer feeding portion 11, impedance matching between the radiating structure 2 and the input port is achieved. The coplanar waveguide transmission line has a simple structure, wide bandwidth, low loss, and is suitable for high-frequency transmission.

[0042] The first metal layer feed portion 11 is further provided with a first metal via 15. The first metal via 15 is symmetrically arranged on both sides of the coplanar waveguide transmission line 14 and is evenly distributed along the longitudinal edge of the coplanar waveguide transmission line 14. The first metal via 15 passes through the dielectric substrate layer feed portion 12 and is connected to the second metal layer feed portion 13. Specifically, the top end of the first metal via 15 is connected to the first metal layer feed portion 11, and the bottom end of the first metal via 15 passes through the dielectric substrate layer feed portion 12 and is connected to the second metal layer feed portion 13. By setting the first metal via 15 and adjusting the distance between the first metal via 15 and the signal line, the impedance is adjusted to achieve impedance matching between the input port and the coplanar waveguide transmission line 14.

[0043] The radiating structure 2 is a substrate integrated waveguide, comprising a first metal layer radiating portion 21, a dielectric substrate layer radiating portion 22, and a second metal layer radiating portion 23 stacked sequentially from top to bottom; the first metal layer radiating portion 21 is printed on the upper surface of the dielectric substrate layer radiating portion 22, and the second metal layer radiating portion 23 is printed on the lower surface of the dielectric substrate layer radiating portion 22; preferably, the peripheral dimensions of the first metal layer radiating portion 21 are: length L2 × width W2 = 106mm × 7.5mm; the peripheral dimensions of the dielectric substrate layer radiating portion of the radiating structure are: length × width × thickness = 106mm × 7.5mm × 0.508mm.

[0044] The first metal layer radiating portion 21 includes a plurality of cells 24 arranged sequentially along the longitudinal center line. A grid window structure 241 is provided on one side of the longitudinal center line of the cell 24, and a row of second metal vias 242 arranged in a straight line is provided on the other side of the longitudinal center line of the cell 24. Two rows of third metal vias 243 arranged in a sawtooth pattern are also provided on both sides of the longitudinal center line of the cell 24.

[0045] Specifically, the grid window structure 241 includes five groups of grid window units arranged in a rectangular array. Each group of grid window units includes two parallel grid windows, both of which are parallel to the longitudinal center line of the cell 24. By setting the grid window structure 241, the electromagnetic energy transmitted in the radiation structure 2 is radiated into free space. By adjusting the size of the grid windows, the magnitude of the electromagnetic energy passing through the grid windows is controlled, thereby obtaining the desired energy distribution throughout the structure.

[0046] The second metal via 242 penetrates the radiating portion 22 of the dielectric substrate layer and connects to the radiating portion 23 of the second metal layer; wherein, the top end of the second metal via 242 is connected to the radiating portion 21 of the first metal layer, and the bottom end of the second metal via 242 penetrates the radiating portion 22 of the dielectric substrate layer and connects to the radiating portion 23 of the second metal layer; by setting the second metal via 242, the impedance matching characteristics of the cell 24 are adjusted; impedance matching is achieved by adjusting the distance between the second metal vias 242 and the distance from the longitudinal centerline.

[0047] One row of serrated third metal vias 243 is located on the outside of the grid window structure 241, and another row of serrated third metal vias 243 is located on the outside of the straight-line distributed second metal vias 242.

[0048] The third metal via 243 penetrates the radiating portion 22 of the dielectric substrate layer and connects to the radiating portion 23 of the second metal layer. The top end of the third metal via 243 is connected to the radiating portion 21 of the first metal layer, and the bottom end of the third metal via 243 penetrates the radiating portion 22 of the dielectric substrate layer and connects to the radiating portion 23 of the second metal layer. By setting the third metal via 243, a metallized via structure is formed on the sidewall of the substrate integrated waveguide transmission line of the main body of the radiating structure 2, ensuring that electromagnetic energy is confined within the waveguide structure and shielding against external electromagnetic interference.

[0049] Working principle:

[0050] The dual circularly polarized leaky antenna based on a substrate integrated waveguide described in this invention, during operation, receives electromagnetic energy through either the first input port 3 or the second input port 4 and transmits it longitudinally along the substrate integrated waveguide structure. Periodically distributed cell 24 along the propagation direction perturbs the electromagnetic energy and generates radiated electromagnetic waves propagating into free space. The amount of electromagnetic energy radiated into free space through the grid window structure can be controlled by adjusting the size of the grid window structure 241 in the cell 24. The grid window structure 241 is optimized according to the Taylor distribution to obtain low sidelobe radiation performance. Different input ports correspond to different circularly polarized radiation characteristics.

[0051] Production process:

[0052] The fabrication process of the dual-circularly polarized leaky antenna based on a substrate integrated waveguide described in this invention is as follows:

[0053] According to the antenna design requirements, an antenna substrate is fabricated using printed circuit board manufacturing technology. The antenna substrate includes a dielectric substrate radiating portion and dielectric substrate feeding portions disposed at both ends of the radiating portion. Then, based on substrate integrated waveguide technology, a first metal via, a second metal via, and a third metal via are added to the antenna substrate. Next, metal layers are printed on the upper and lower surfaces of the antenna substrate to obtain the first metal layer feeding portion, the first metal layer radiating portion, the second metal layer feeding portion, and the second metal layer radiating portion. Gold plating is applied to the surface of the antenna substrate to achieve the printing of the metal layers.

[0054] The dual circularly polarized leaky antenna of this invention achieves precise fabrication of the leaky antenna in the millimeter-wave band by combining leaky antenna and substrate integrated waveguide technology. It features a wide axial ratio, high bandwidth, low sidelobes, large scanning range, low profile, and low cost, enabling broadband, low sidelobes, and wide-angle scanning. Specifically, the wide bandwidth, low sidelobes, and wide-angle scanning circular polarization performance are achieved through the design of a grid window structure, optimization of the Taylor amplitude distribution at the distance from the longitudinal centerline, and the loading of metal vias. The combination of substrate integrated waveguide technology and the leaky antenna achieves high-precision and low-cost fabrication, effectively reducing the accuracy issues associated with leaky antenna fabrication in the millimeter-wave band. Specifically, the leaky antenna is fabricated using substrate integrated waveguide technology, and the addition of metal vias in the dielectric substrate achieves the low insertion loss, low radiation, and high power capacity of traditional rectangular waveguides, offering advantages such as high integration, low loss, mature fabrication technology, low cost, and high precision.

[0055] As attached Figure 5 As shown, attached Figure 5 The simulation structure diagram of the reflection coefficient of the leaky wave antenna is given in the appendix; Figure 5As can be seen from the data, within the frequency range of 25.6GHz-38.3GHz, |S 11 |<-10dB, relative bandwidth is 39.7%. (See attached image) Figure 6 As shown, attached Figure 6 The frequency-phase relationship of the cells is given in the appendix; Figure 6 As can be seen from the data, the phase value of the dual circularly polarized leaky wave antenna in the frequency range of 25GHz-38.5GHz is smaller than that in free space, that is, the antenna operates in the fast wave region in this frequency band, with a relative bandwidth of 43%.

[0056] As attached Figure 7 As shown, attached Figure 7 The results show the right-hand circular polarization gain patterns of the dual-circular polarization leaky antenna fed from the first input port at 25.8 GHz, 27.5 GHz, 29.0 GHz, 32.0 GHz, 35.0 GHz, and 37.7 GHz; see the appendix. Figure 7 As can be seen, the scanning range of the dual-circularly polarized leaky antenna is -50° to 31°; specifically, at 32 GHz, the sidelobe level is -15.4 dB; as shown in the attached figure. Figure 8 As shown, attached Figure 8 The results of the right-hand circular polarization axial ratio for the dual circularly polarized leaky antenna fed from the first input port at 25.8 GHz, 27.5 GHz, 29.0 GHz, 32.0 GHz, 35.0 GHz, and 37.7 GHz are given; from the appendix... Figure 8 As can be seen, the axial ratio AR is less than 3dB and the relative bandwidth is 37.7% across the entire scanning range of the antenna.

[0057] As attached Figure 9 As shown, attached Figure 9 The results show the left-hand circular polarization gain patterns of the dual-circular polarization leaky antenna fed from the second input port at 25.8 GHz, 27.5 GHz, 29.0 GHz, 32.0 GHz, 35.0 GHz, and 37.7 GHz; see the appendix. Figure 9 As can be seen, the antenna's scanning range is 50° to -31°; at 32 GHz, the sidelobe level is -15.4 dB; as shown in the attached figure. Figure 10 As shown, attached Figure 10 The results for the left-hand circular polarization axial ratio of the dual-circularly polarized leaky antenna fed from the second input port are given at 25.8 GHz, 27.5 GHz, 29.0 GHz, 32.0 GHz, 35.0 GHz, and 37.7 GHz; from the appendix... Figure 10 As can be seen, the axial ratio AR is less than 3dB and the relative bandwidth is 37.7% across the entire scanning range of the antenna.

[0058] As attached Figure 11 As shown, attached Figure 11 The figure shows the simulation results of the gain of the dual-circularly polarized leaky wave antenna as a function of frequency; from the appendix... Figure 11 As can be seen, the dual-circularly polarized leaky antenna has a gain greater than 13.2 dBic in the frequency range of 25.6 GHz to 38.3 GHz; the maximum gain is 17.2 dBic at 34 GHz; see attached. Figure 12 As shown, attached Figure 12 The figure shows the simulation results of the radiation efficiency of the dual-circularly polarized leaky wave antenna as a function of frequency; from the appendix... Figure 12 It can be seen that the dual-circularly polarized leaky antenna has a radiation efficiency of more than 59% in the frequency range of 25.8GHz-37.3GHz; among which, the maximum radiation efficiency is 83% at 37.7GHz.

[0059] In this invention, a low-profile and low-cost SIW (Self-Impacted Waveguide) is used as the radiating antenna, and a gradient grounded coplanar waveguide (GCPW) is used as the feed input. This achieves a wideband, low-sidelobe, wide-angle scanning circularly polarized leaky antenna that is easy to integrate into millimeter-wave wireless systems. Specifically, the feed structure, from top to bottom, consists of a first metal layer feed section, a dielectric substrate layer feed section, and a second metal layer feed section. The first metal layer feed section has a gradient coplanar waveguide transmission line, and two rows of first metallized vias are arranged on both sides of the coplanar waveguide transmission line. The second metal layer feed section serves as the ground metal layer of the feed structure. The radiating structure, from top to bottom, consists of a first metal layer radiating section, a dielectric substrate layer radiating section, and a second metal layer radiating section. In the first metal layer radiating section, a plurality of grid window structures are arranged, which are evenly distributed along the longitudinal centerline of the first metal layer radiating section and located on one side of the longitudinal centerline of the first metal layer radiating section; a row of second metal vias arranged in a straight line are evenly distributed along the longitudinal centerline of the first metal layer radiating section and located on the other side of the longitudinal centerline of the first metal layer radiating section; two rows of third metal vias arranged in a sawtooth pattern are symmetrically arranged along the longitudinal centerline of the first metal layer radiating section, wherein one row of third metal vias arranged in a sawtooth pattern is located outside the grid window structures, and the other row of third metal vias arranged in a sawtooth pattern is located outside the second metal vias arranged in a straight line.

[0060] The dual-circularly polarized leaky antenna based on substrate integrated waveguide described in this invention combines leaky antenna and substrate integrated waveguide technology. It designs a gradually changing coplanar waveguide transmission line on the feeding structure and a grid window leaky structure along the radiation structure, thus achieving the requirements of the millimeter-wave operating frequency band. It features a wide axial ratio bandwidth, low sidelobes, large scanning range, low profile, and low cost. It solves the technical problems of narrow axial ratio bandwidth, narrow beam scanning range, and poor anti-interference capability of millimeter-wave leaky antennas.

[0061] In this invention, high-performance leakage radiation is achieved through a grid window leakage structure on the first metal layer of the radiating structure, combining the low profile, ease of fabrication, and ease of integration characteristics of SIW structures. Secondly, by adjusting the size of the grid window structure in each cell, the amount of leaked electromagnetic energy can be effectively controlled, enabling a broadband, low-sidelobe, wide-angle scanning dual-circularly polarized leakage antenna for millimeter-wave communication bands. The dual-circularly polarized leakage antenna described in this invention operates within the frequency range of 25.6 GHz to 38.3 GHz. 11 | < -10dB, relative bandwidth is 39.7%; in the frequency range of 25.8GHz-37.7GHz, AR < 3dB, relative bandwidth is 37.7%, beam scanning range is 81° (-31°~50°), gain range is 13.2dBic-17.2dBic; at 32GHz, the sidelobe level is -15.4dB.

[0062] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A dual-circularly polarized leaky antenna based on a substrate integrated waveguide, characterized in that, It includes a feeding structure (1) and a radiating structure (2); the feeding structure (1) is symmetrically arranged at both ends of the radiating structure (2), and both the feeding structure (1) and the radiating structure (2) are substrate integrated waveguides; The feeding structure (1) is used to convert the received external electromagnetic energy into guided electromagnetic waves and has the characteristic of broadening impedance; wherein, the feeding structure (1) is designed with a gradually changing coplanar waveguide transmission line. The radiation structure (2) is used to convert the guided electromagnetic wave transmitted by the feed structure (1) into a circularly polarized electromagnetic wave in free space; wherein, the radiation structure (2) is designed with a grid window leakage structure. The power feeding structure (1) includes a first metal layer power feeding part (11), a dielectric substrate layer power feeding part (12) and a second metal layer power feeding part (13) stacked sequentially from top to bottom. A coplanar waveguide transmission line (14) is arranged on the longitudinal center line of the first metal layer feeding part (11). The coplanar waveguide transmission line (14) is a gradually changing coplanar waveguide transmission line. The gradually changing coplanar waveguide transmission line includes a straight segment and a trapezoidal gradually changing segment. The first end of the straight segment is the input end of the feeding structure (1). The second end of the straight segment is connected to the small-sized end of the trapezoidal gradually changing segment. The large-sized end of the trapezoidal gradually changing segment is connected to the radiation structure (2). The radiation structure (2) includes a first metal layer radiation portion (21), a dielectric substrate layer radiation portion (22) and a second metal layer radiation portion (23) stacked sequentially from top to bottom. The first metal layer radiation portion (21) includes a number of cells (24) arranged sequentially along the longitudinal center line; a grid window structure (241) is provided on one side of the longitudinal center line of the cell (24), and a row of second metal vias (242) arranged in a straight line is provided on the other side of the longitudinal center line of the cell (24). Two rows of third metal vias (243) are provided on both sides of the longitudinal center line of the cell (24); one row of third metal vias (243) is located outside the grid window structure (241), and the other row of third metal vias (243) is located outside the second metal vias (242) which are arranged in a straight line.

2. The dual-circularly polarized leaky antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The first metal layer feed portion (11) is further provided with a first metal via (15). The first metal via (15) is symmetrically arranged on both sides of the coplanar waveguide transmission line (14) and is evenly distributed along the longitudinal edge of the coplanar waveguide transmission line (14). The first metal via (15) passes through the dielectric substrate layer feed portion (12) and is connected to the second metal layer feed portion (13).

3. The dual-circularly polarized leaky antenna based on a substrate integrated waveguide according to claim 1, characterized in that, It also includes an input port, which is located at the end of the power supply structure (1) and connected to the first end of the straight segment.

4. The dual-circularly polarized leaky antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The first metal layer feed portion (11) is printed on the upper surface of the dielectric substrate layer feed portion (12), and the second metal layer feed portion (13) is printed on the lower surface of the dielectric substrate layer feed portion (12).

5. A dual-circularly polarized leaky antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The top end of the second metal via (242) is connected to the first metal layer radiating portion (21), and the bottom end of the second metal via (242) passes through the dielectric substrate layer radiating portion (22) and is connected to the second metal layer radiating portion (23).

6. A dual-circularly polarized leaky antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The top end of the third metal via (243) is connected to the first metal layer radiating portion (21), and the bottom end of the third metal via (243) passes through the dielectric substrate layer radiating portion (22) and is connected to the second metal layer radiating portion (23).

7. A dual-circularly polarized leaky antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The first metal layer radiating portion (21) is printed on the upper surface of the dielectric substrate layer radiating portion (22), and the second metal layer radiating portion (23) is printed on the lower surface of the dielectric substrate layer radiating portion (22).

8. A dual-circularly polarized leaky antenna based on a substrate integrated waveguide according to claim 1, characterized in that, The grid window structure (241) includes four groups of grid window units arranged in a rectangular array. Each group of grid window units includes two grid windows arranged in parallel, and both grid windows are parallel to the vertical center line of the cell (24).

Images