Dual circularly polarized leaky-wave antenna based on substrate integrated waveguide

Abstract

The invention belongs to the technical field of antennas, and discloses a dual circularly polarized leaky-wave antenna based on a substrate integrated waveguide, which comprises a feed structure and a radiation structure, the feed structures are symmetrically arranged at the two ends of the radiation structure, and the feed structures and the radiation structure are substrate integrated waveguides; the feed structure is used for converting received external electromagnetic energy into guided electromagnetic waves and has the characteristic of widening impedance; wherein a gradient coplanar waveguide transmission line is designed in the feed structure; the radiation structure is used for converting the guided electromagnetic waves transmitted by the feed structure into circularly polarized electromagnetic waves in a free space; wherein a grid window leaky wave structure is designed in the radiation structure; by combining the leaky-wave antenna and the substrate integrated waveguide technology, the gradient coplanar waveguide transmission line is designed on the feed structure, and the grid window leaky-wave structure is designed on the radiation structure, so that the millimeter wave working frequency band requirement is met, and the antenna has the characteristics of wide axial ratio bandwidth, low side lobe, large scanning range, low profile and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a dual circularly polarized leaky wave antenna based on a substrate integrated waveguide. Background Art

[0002] Leaky-Wave Antenna (LWA) is a traveling wave antenna with the characteristics of wide bandwidth, beam scanning capability, easy integration and low cost. With the development of modern wireless communication technology, the millimeter wave band has attracted more and more attention due to its advantages such as high communication capacity and strong anti-interference ability. Millimeter wave leaky wave antenna has the above advantages and has been widely developed and applied in radar systems, 5G communications, sensing and other fields.

[0003] As a key component in wireless communications, millimeter-wave leaky-wave antennas play a vital 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 directionality. Most of the existing leaky-wave antennas are linearly polarized, and have problems such as polarization mismatch and poor anti-multipath effect, which affect the communication quality. Circularly polarized antennas have the ability to resist polarization loss and effectively suppress multipath interference, especially in mobile communications. This advantage is more prominent. Therefore, circularly polarized antennas can effectively improve the reliability and stability of the system. However, existing circularly polarized millimeter-wave leaky-wave antennas generally have technical problems such as narrow axial ratio bandwidth, narrow beam scanning range and poor antenna anti-interference ability. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a dual circularly polarized leaky-wave antenna based on a substrate integrated waveguide to solve the technical problems of the existing circularly polarized millimeter-wave leaky-wave antenna, such as narrow axial ratio bandwidth, narrow beam scanning range and poor antenna anti-interference ability.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a dual circular polarization leaky wave antenna based on substrate integrated waveguide, comprising 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 to convert the received external electromagnetic energy into guided electromagnetic waves and has the characteristic of widening impedance; wherein a gradual coplanar waveguide transmission line is designed in the feeding structure; 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 a grid window leaky wave structure is designed in the radiation structure.

[0006] Furthermore, the feeding structure comprises a first metal layer feeding part, a dielectric substrate layer feeding part and a second metal layer feeding part which are stacked in sequence from top to bottom; A coplanar waveguide transmission line is arranged on the longitudinal center line of the first metal layer feeding part, and the coplanar waveguide transmission line is a gradient coplanar waveguide transmission line; wherein the gradient coplanar waveguide transmission line includes a straight line segment and a trapezoidal gradient segment; the first end of the straight line segment is the input end of the feeding structure, the second end of the straight line 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 radiation structure.

[0007] Furthermore, a first metal via is provided on the first metal layer feeding part, and the first metal via is symmetrically arranged on both sides of the coplanar waveguide transmission line and evenly distributed along the longitudinal edge of the coplanar waveguide transmission line; wherein, the first metal via passes through the dielectric substrate layer feeding part and is connected to the second metal layer feeding part.

[0008] Furthermore, it also includes an output port, and the input port is arranged at the end of the feeding structure and connected to the first end of the straight line segment.

[0009] Furthermore, the first metal layer feeding part is printed on the upper surface of the dielectric substrate layer feeding part, and the second metal layer feeding part is printed on the lower surface of the dielectric substrate layer feeding part.

[0010] Furthermore, the radiation structure includes a first metal layer radiation part, a dielectric substrate layer radiation part and a second metal layer radiation part which are stacked in sequence from top to bottom; The radiation portion of the first metal layer includes a plurality of cells sequentially distributed along a longitudinal center line; a grid window structure is provided on one side of the longitudinal center line of the cell, and a row of second metal vias distributed in a straight line is provided on the other side of the longitudinal center line of the cell; Two rows of third metal vias distributed in a zigzag pattern are also arranged on both sides of the longitudinal center line of the unit cell; one row of the third metal vias distributed in a zigzag pattern is located outside the grid window structure, and the other row of the third metal vias distributed in a zigzag pattern is located outside the second metal vias distributed in a straight line.

[0011] 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 then is connected to the radiating portion of the second metal layer.

[0012] Furthermore, the top end of the third metal via is connected to the radiation part of the first metal layer, and the bottom end of the second metal via penetrates the radiation part of the dielectric substrate layer and then is connected to the radiation part of the second metal layer.

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

[0014] Furthermore, the grid window structure includes four groups of grid window units distributed in a rectangular array, each group of the grid window units includes two grid windows arranged in parallel, and the two grid windows are parallel to the longitudinal center line of the unit cell.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The dual circularly polarized leaky wave antenna based on substrate integrated waveguide provided by the present invention realizes the requirements of millimeter wave working frequency band by combining leaky wave antenna and substrate integrated waveguide technology, designs a gradual coplanar waveguide transmission line on the feeding structure, and designs a grid window leaky wave structure on the radiation structure, and has the characteristics of wide bandwidth, low side lobe, large scanning range, low profile and low cost with axial ratio; specifically, by adjusting the size of the grid window leaky wave structure, the size of the leaked electromagnetic energy can be effectively controlled, thereby meeting the broadband, low side lobe and wide-angle scanning dual circularly polarized leaky wave antenna of the millimeter wave communication frequency band; wherein, the dual circularly polarized leaky wave antenna is within the frequency range of 25.6GHz-38.3GHz|S 11 |<-10dB, the relative bandwidth is 39.7%; in the frequency range of 25.8GHz-37.7GHz, AR<3dB, the relative bandwidth is 37.7%, the beam scanning range is 81° (-31°~50°), the gain range is 13.2dBic-17.2dBic, and the sidelobe level is -15.4dB at 32GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of a three-dimensional layered structure of a substrate integrated waveguide-based dual circularly polarized leaky wave antenna according to the present invention; Figure 2 is a plan view schematic diagram of the feeding structure in the present invention; Figure 3 is a plan view schematic diagram of the radiation structure in the present invention; Figure 4 It is a plan view of a unit cell in the present invention; Figure 5 It is a reflection coefficient simulation structure diagram of the dual circular polarization leaky wave antenna in the present invention; Figure 6 A frequency-phase relationship diagram of a cell in the present invention; Figure 7 is the right-hand circularly polarized gain pattern of the dual circularly polarized leaky-wave antenna in the present invention; Figure 8 is a right-hand circular polarization axis ratio diagram of the dual circular polarization leaky wave antenna in the present invention; Fig. 9 is the left-hand circularly polarized gain pattern of the dual circularly polarized leaky-wave antenna in the present invention; Fig.10 It is a left-hand circular polarization axis ratio diagram of the dual circular polarization leaky wave antenna in the present invention; Fig.11 : is a simulation result diagram of the gain variation of the dual circularly polarized leaky wave antenna with frequency in the embodiment; Fig.12 This is a simulation result diagram of the radiation efficiency of the dual circularly polarized leaky wave antenna in the present invention changing with frequency.

[0018] Among them, 1 is a feeding structure, 2 is a radiation structure, 3 is a first input port, 4 is a second input port; 11 is a first metal layer feeding part, 12 is a dielectric substrate layer feeding part, 13 is a second metal layer feeding part, 14 is a coplanar waveguide transmission line, 15 is a first metal via; 21 is a first metal layer radiation part, 22 is a dielectric substrate layer radiation part, 23 is a second metal layer radiation part, 24 is a unit cell; 241 is a grid window structure, 242 is a second metal via, and 243 is a third metal via. DETAILED DESCRIPTION

[0019] In order 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 described clearly and completely in combination with the drawings in the embodiments of this application; obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] As attached Figure 1-4 As shown, the present invention provides a dual circularly polarized leaky wave antenna based on substrate integrated waveguide, comprising 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.

[0021] 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 a guided electromagnetic wave, and has the characteristic of widening impedance; the radiation structure 2 is used to convert the guided electromagnetic wave transmitted by the feeding structure 1 into a circularly polarized electromagnetic wave in free space.

[0022] The feeding structure 1 is a substrate integrated waveguide, comprising a first metal layer feeding part 11, a dielectric substrate layer feeding part 12 and a second metal layer feeding part 13 which are stacked in sequence from top to bottom; the first metal layer feeding part 11 is printed on the upper surface of the dielectric substrate layer feeding part 12, and the second metal layer feeding part 13 is printed on the lower surface of the dielectric substrate layer feeding part 12; preferably, the outer dimension characteristics of the first metal layer feeding part 11 are: length L1×width W1=15mm×13mm; the outer dimension characteristics of the dielectric substrate layer feeding part 12 are: length×width×thickness=15mm×13mm×0.508mm.

[0023] A coplanar waveguide transmission line 14 is arranged on the longitudinal center line of the first metal layer feeding part 11, and the coplanar waveguide transmission line 14 is a gradient coplanar waveguide transmission line; specifically, the gradient coplanar waveguide transmission line includes a straight section and a trapezoidal gradient section, and the straight section and the trapezoidal gradient section are along the longitudinal center line of the first metal layer feeding part 11, and are sequentially arranged from the input end to the output end of the feeding structure 1; the first end of the straight section 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 section is connected to the small-sized end of the trapezoidal gradient section, and the large-sized end of the trapezoidal gradient section is connected to the end of the radiation structure 2; it should be noted that by arranging a gradient coplanar waveguide transmission line on the longitudinal center line of the first metal layer feeding part 11, impedance matching between the radiation structure 2 and the input port is achieved, and the coplanar waveguide transmission line has a simple structure, broadband, low loss, and is suitable for high-frequency transmission.

[0024] The first metal layer feeding part 11 is also provided with a first metal via 15, which is symmetrically arranged on both sides of the coplanar waveguide transmission line 14 and evenly distributed along the longitudinal edge of the coplanar waveguide transmission line 14; wherein, the first metal via 15 penetrates the dielectric substrate layer feeding part 12 and is connected to the second metal layer feeding part 13; specifically, the top end of the first metal via 15 is connected to the first metal layer feeding part 11, and the bottom end of the first metal via 15 penetrates the dielectric substrate layer feeding part 12 and is connected to the second metal layer feeding part 13; by setting the first metal via 15, the distance between the first metal via 15 and the signal line is adjusted to adjust the impedance, so as to achieve impedance matching between the input and output ports and the coplanar waveguide transmission line 14.

[0025] The radiation structure 2 is a substrate integrated waveguide, including a first metal layer radiation part 21, a dielectric substrate layer radiation part 22 and a second metal layer radiation part 23 which are stacked in sequence from top to bottom; the first metal layer radiation part 21 is printed on the upper surface of the dielectric substrate layer radiation part 22, and the second metal layer radiation part 23 is printed on the lower surface of the dielectric substrate layer radiation part 22; preferably, the outer dimension characteristics of the first metal layer radiation part 21 are: length L2×width W2=106mm×7.5mm; the outer dimension characteristics of the dielectric substrate layer radiation part of the radiation structure are: length×width×thickness=106mm×7.5mm×0.508mm.

[0026] The first metal layer radiation part 21 includes a plurality of cells 24 distributed in sequence along the longitudinal center line, a grid window structure 241 is arranged on one side of the longitudinal center line of the cell 24, a row of second metal vias 242 distributed in a straight line is arranged on the other side of the longitudinal center line of the cell 24, and two rows of third metal vias 243 distributed in a zigzag shape are also arranged on both sides of the longitudinal center line of the cell 24.

[0027] Specifically, the grid window structure 241 includes five groups of grid window units distributed in a rectangular array, each group of the grid window units includes two parallel grid windows, and the two grid windows are parallel to the longitudinal center line of the unit cell 24; by setting the grid window structure 241, the electromagnetic energy transmitted in the radiation structure 2 is radiated into the free space; by adjusting the size of the grid window, the size of the electromagnetic energy passing through the grid window can be controlled, so as to obtain the desired energy distribution on the entire structure.

[0028] The second metal via 242 penetrates the dielectric substrate layer radiation part 22 and is connected to the second metal layer radiation part 23; wherein, the top end of the second metal via 242 is connected to the first metal layer radiation part 21, and the bottom end of the second metal via 242 penetrates the dielectric substrate layer radiation part 22 and is connected to the second metal layer radiation part 23; the impedance matching characteristics of the unit cell 24 are adjusted by setting the second metal via 242; impedance matching is achieved by adjusting the distance between the second metal vias 242 and the distance from the longitudinal center line.

[0029] One row of the third metal vias 243 distributed in a zigzag shape is located outside the grid window structure 241, and another row of the third metal vias 243 distributed in a zigzag shape is located outside the second metal vias 242 distributed in a straight line; The third metal via 243 penetrates the dielectric substrate layer radiation part 22 and is connected to the second metal layer radiation part 23; wherein, the top end of the third metal via 243 is connected to the first metal layer radiation part 21, and the bottom end of the third metal via 243 penetrates the dielectric substrate layer radiation part 22 and is connected to the second metal layer radiation part 23; by setting the third metal via 243, the side wall metallized through-hole structure of the substrate integrated waveguide transmission line of the main part of the radiation structure 2 is formed, ensuring that the electromagnetic energy is confined in the waveguide structure and can shield external electromagnetic interference.

[0030] Working principle: The dual circularly polarized leaky wave antenna based on substrate integrated waveguide described in the present invention, when working, electromagnetic energy is input from the first input port 3 or the second input port 4, and is transmitted along the longitudinal direction of the substrate integrated waveguide structure, and the cells 24 periodically distributed along the propagation direction perturb the electromagnetic energy and generate radiated electromagnetic waves propagating into the free space; by adjusting the size of the grid window structure 241 in the cell 24, the size of the electromagnetic energy radiated into the free space through the grid window structure can be controlled, and the grid window structure 241 is optimized according to Taylor distribution to obtain radiation performance with low side lobes; different input ports correspond to different circularly polarized radiation characteristics.

[0031] Production process: The manufacturing process of the substrate integrated waveguide-based dual circularly polarized leaky wave antenna of the present invention is as follows: According to the design requirements of the antenna, the printed circuit board manufacturing process is adopted to obtain the antenna substrate; wherein the antenna substrate includes a dielectric substrate layer radiation part and a dielectric substrate layer feeding part arranged at both ends of the dielectric substrate layer radiation part; then, according to the substrate integrated waveguide technology, a first metal via, a second metal via and a third metal via are added to the antenna substrate; then, metal layers are printed on the upper and lower surfaces of the antenna substrate to obtain a first metal layer feeding part, a first metal layer radiation part, a second metal layer feeding part and a second metal layer radiation part; wherein, the surface of the antenna substrate is gold-plated to realize the printing of the metal layer.

[0032] The dual circularly polarized leaky wave antenna described in the present invention realizes precise processing of the leaky wave antenna in the millimeter wave frequency band by combining the leaky wave antenna and substrate integrated waveguide technology; it has the characteristics of wide bandwidth, low side lobe, large scanning range, low profile and low cost of axial ratio, and can realize broadband, low side lobe and wide-angle scanning of the antenna; wherein, by designing the grid window structure, optimizing the Taylor amplitude distribution at the distance from the longitudinal center line position, and loading the metal vias, the circular polarization performance of the antenna with broadband, low side lobe and wide-angle scanning is realized; the substrate integrated waveguide technology is combined with the leaky wave antenna to realize high-precision and low-cost processing of the antenna, which can well reduce the processing accuracy problem of the leaky wave antenna in the millimeter wave frequency band; specifically, the leaky wave antenna is processed by using the substrate integrated waveguide technology, and the low insertion loss, low radiation, high power capacity and other performances of the traditional rectangular waveguide are realized by adding metal vias in the dielectric substrate, and it has the advantages of high integration, low loss, mature processing technology, low cost and high precision.

[0033] As attached Figure 5 As shown, attached Figure 5 The reflection coefficient simulation structure diagram of the leaky wave antenna is given in the figure; Figure 5 It can be seen that the dual circularly polarized leaky wave antenna has a frequency range of 25.6 GHz to 38.3 GHz. 11 |<-10dB, the relative bandwidth is 39.7%. Figure 6 As shown, attached Figure 6 The frequency-phase relationship diagram of the unit cell is given in the figure; Figure 6 It can be seen that the phase values ​​of the dual circularly polarized leaky wave antenna in the frequency range of 25 GHz-38.5 GHz are all smaller than those in free space, that is, the antenna works in the fast wave region in this frequency band, and the relative bandwidth is 43%.

[0034] As attached Figure 7 As shown, attached Figure 7 The right-hand circularly polarized gain pattern results of the dual circularly polarized leaky wave antenna fed by 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 in the attached figure. Figure 7 It can be seen that the scanning range of the dual circular polarization leaky wave antenna is the beam scanning range of -50°~31°; among them, at 32GHz, the sidelobe level is -15.4dB; as shown in the attached Figure 8 As shown, attached Figure 8 The right-hand circular polarization axis ratio results at 25.8 GHz, 27.5 GHz, 29.0 GHz, 32.0 GHz, 35.0 GHz, and 37.7 GHz are given in the figure when the dual circularly polarized leaky wave antenna is fed by the first input port; Figure 8 It can be seen that the axial ratio AR of the antenna in the entire scanning range is <3dB, and the relative bandwidth is 37.7%.

[0035] As attached Fig. 9 As shown, attached Fig. 9 The left-hand circularly polarized gain pattern results of the dual circularly polarized leaky wave antenna fed by the second input port at 25.8 GHz, 27.5 GHz, 29.0 GHz, 32.0 GHz, 35.0 GHz and 37.7 GHz are given in the attached figure. Fig. 9 It can be seen that the scanning range of the antenna is 50°~-31°; among them, at 32GHz, the sidelobe level is -15.4dB; as shown in the attached Fig.10 As shown, attached Fig.10 The left-hand circular polarization axis ratio results at 25.8 GHz, 27.5 GHz, 29.0 GHz, 32.0 GHz, 35.0 GHz, and 37.7 GHz are given in the figure when the dual circularly polarized leaky wave antenna is fed by the second input port; Fig.10 It can be seen that the axial ratio AR of the antenna in the entire scanning range is <3dB, and the relative bandwidth is 37.7%.

[0036] As attached Fig.11 As shown, attached Fig.11 The simulation results of the gain variation of the dual circularly polarized leaky wave antenna with frequency are given in the figure; Fig.11 It can be seen that the dual circular polarization leaky wave antenna has a gain greater than 13.2dBic in the frequency range of 25.6GHz-38.3GHz; the maximum gain is 17.2dBic at 34GHz; as shown in the attached Fig.12 As shown, attached Fig.12 The simulation results of the radiation efficiency of the dual circularly polarized leaky wave antenna varying with frequency are given in the figure; Fig.12 It can be seen that the radiation efficiency of the dual circularly polarized leaky-wave antenna is greater than 59% in the frequency range of 25.8 GHz-37.3 GHz; among them, the maximum radiation efficiency is 83% at 37.7 GHz.

[0037] In the present invention, a SIW with a low profile and low cost is used as a radiating antenna, and a gradient grounded coplanar waveguide (GCPW) is used as a feeding input, so as to realize a circularly polarized leaky wave antenna with a broadband, low sidelobe and wide-angle scanning that is easy to integrate and meets the requirements of a millimeter wave wireless system; specifically, the feeding structure is, from top to bottom, a first metal layer feeding part, a dielectric substrate layer feeding part and a second metal layer feeding part, the first metal layer feeding part is arranged with a gradient coplanar waveguide transmission line, two rows of first metalized vias are arranged on both sides of the coplanar waveguide transmission line, and the second metal layer feeding part serves as a grounded metal layer of the feeding structure; the radiating structure is, from top to bottom, a first metal layer radiating part, a dielectric substrate layer radiating part and a second metal layer radiating part. The radiation part of the first metal layer is provided with a plurality of grid window structures, and the plurality of grid window structures are evenly distributed along the longitudinal center line of the radiation part of the first metal layer and are located on one side of the longitudinal center line of the radiation part of the first metal layer; a row of second metal vias arranged in a straight line are evenly distributed along the longitudinal center line of the radiation part of the first metal layer and are located on the other side of the longitudinal center line of the radiation part of the first metal layer; two rows of third metal vias distributed in a zigzag line are symmetrically arranged along the longitudinal center line of the radiation part of the first metal layer, wherein one row of the third metal vias distributed in a zigzag line is located on the outside of the grid window structure, and the other row of the third metal vias distributed in a zigzag line is located on the outside of the second metal vias distributed in a straight line.

[0038] The dual circularly polarized leaky-wave antenna based on substrate integrated waveguide described in the present invention realizes the requirements of the millimeter-wave working frequency band by combining the leaky-wave antenna and substrate integrated waveguide technology, designs a gradient coplanar waveguide transmission line on the feeding structure, and designs a grid window leaky-wave structure on the radiation structure; it has the characteristics of wide axial ratio bandwidth, low side lobe, 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 ability of millimeter-wave leaky-wave antenna.

[0039] In the present invention, high-performance leaky wave radiation is achieved through the grid window leaky wave structure on the first metal layer of the radiation structure, and the characteristics of low profile, easy processing and easy integration of the SIW structure are combined; secondly, by adjusting the size of the grid window structure in each unit cell, the size of the leaked electromagnetic energy can be effectively controlled, and a broadband, low sidelobe, wide-angle scanning dual circularly polarized leaky wave antenna in the millimeter wave communication frequency band can be realized; the dual circularly polarized leaky wave antenna described in the present invention has a frequency range of 25.6GHz-38.3GHz|S 11 |<-10dB, the relative bandwidth is 39.7%; in the frequency range of 25.8GHz-37.7GHz, AR<3dB, the relative bandwidth is 37.7%, the beam scanning range is 81° (-31°~50°), and the gain range is 13.2dBic-17.2dBic; at 32GHz, the sidelobe level is -15.4dB.

[0040] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A dual circularly polarized leaky wave antenna based on substrate integrated waveguide, characterized in that: It comprises a feeding structure (1) and a radiating structure (2); the feeding structure (1) is symmetrically arranged at two 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 received external electromagnetic energy into guided electromagnetic waves and has the characteristic of widening impedance; wherein a gradient coplanar waveguide transmission line is designed in the feeding structure (1); 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; wherein a grid window leaky wave structure is designed in the radiation structure (2).

2. A dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 1, characterized in that: The feeding structure (1) comprises a first metal layer feeding part (11), a dielectric substrate layer feeding part (12) and a second metal layer feeding part (13) which are stacked in sequence 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), and the coplanar waveguide transmission line (14) is a gradient coplanar waveguide transmission line; wherein the gradient coplanar waveguide transmission line comprises a straight section and a trapezoidal gradient section; the first end of the straight section is the input end of the feeding structure (1), the second end of the straight section is connected to the small-sized end of the trapezoidal gradient section, and the large-sized end of the trapezoidal gradient section is connected to the radiation structure (2).

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

4. A dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 2, characterized in that: It also includes an output port, wherein the input port is arranged at the end of the feeding structure (1) and is connected to the first end of the straight line segment.

5. The dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 2, characterized in that: The first metal layer feeding part (11) is printed on the upper surface of the dielectric substrate layer feeding part (12), and the second metal layer feeding part (13) is printed on the lower surface of the dielectric substrate layer feeding part (12).

6. The dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 1, characterized in that: The radiation structure (2) comprises a first metal layer radiation part (21), a dielectric substrate layer radiation part (22) and a second metal layer radiation part (23) which are stacked in sequence from top to bottom; The first metal layer radiation portion (21) comprises a plurality of cells (24) sequentially distributed along a 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) distributed 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) distributed in a zigzag pattern are also provided on both sides of the longitudinal center line of the unit cell (24); one row of the third metal vias (243) distributed in a zigzag pattern is located outside the grid window structure (241), and the other row of the third metal vias (243) distributed in a zigzag pattern is located outside the second metal vias (242) distributed in a straight line.

7. A dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 6, characterized in that: The top end of the second metal via (242) is connected to the first metal layer radiation part (21), and the bottom end of the second metal via (242) passes through the dielectric substrate layer radiation part (22) and is connected to the second metal layer radiation part (23).

8. The dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 6, characterized in that: The top end of the third metal via (243) is connected to the first metal layer radiation part (21), and the bottom end of the second metal via (243) penetrates the dielectric substrate layer radiation part (22) and is connected to the second metal layer radiation part (23).

9. The dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 6, characterized in that: The first metal layer radiation part (21) is printed on the upper surface of the dielectric substrate layer radiation part (22), and the second metal layer radiation part (23) is printed on the lower surface of the dielectric substrate layer radiation part (22).

10. The dual circularly polarized leaky wave antenna based on substrate integrated waveguide according to claim 6, characterized in that: The grid window structure (241) comprises four groups of grid window units distributed in a rectangular array, each group of the grid window units comprises two grid windows arranged in parallel, and the two grid windows are parallel to the longitudinal center line of the unit cell (24).

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