A waveguide conversion structure for a LOP waveguide antenna

Abstract

The application discloses a waveguide conversion structure of an LOP waveguide antenna, which comprises an analog PCB board and a waveguide conversion structure body, the analog PCB board is provided with four receiving ports and four transmitting ports, the waveguide conversion structure body is provided with four upper waveguides and four lower waveguides, the four upper waveguides are arranged on the upper side of the waveguide conversion structure body, the four lower waveguides are arranged on the lower side of the waveguide conversion structure body, one end of two upper waveguides and two lower waveguides is connected with the four receiving ports of the analog PCB board, and one end of the other two upper waveguides and the other two lower waveguides is connected with the four transmitting ports of the analog PCB board. The application adopts a transition groove and a vertical transition scheme of twice signals, solves the problem of adjacent port wire-out interference, realizes the application of a single-layer waveguide antenna in the LOP waveguide antenna, and has the processing production feasibility under the working frequency band of 77GHz.

Description

Technical Field

[0001] This invention relates to a waveguide conversion structure, and more particularly to a waveguide conversion structure for a LOP waveguide antenna, belonging to the field of antenna technology. Background Technology

[0002] A single-layer waveguide antenna is an antenna design based on a waveguide structure. Compared to traditional multi-layer or complex antenna structures, it has advantages such as simple structure, low manufacturing cost, and ease of integration. In recent years, with the development of technologies such as 5G / 6G communication, millimeter-wave radar, and satellite communication, single-layer waveguide antennas have attracted widespread attention due to their excellent performance in the high-frequency band.

[0003] Chinese Patent No. CN117941173A discloses an open waveguide antenna and a system having an open waveguide antenna, comprising: an electromagnetic transition section (EM) having a transition region, a signal feed interface, and an open waveguide section; the EM transition section is configured to couple EM energy from the signal feed interface to a guiding waveguide mode of EM energy via the transition region to the open waveguide section; and a leaky waveguide antenna section configured to radiate electromagnetic energy received from the open waveguide section; wherein the EM transition section is electromagnetically coupled to the leaky waveguide antenna section, and the EM transition section is configured to support the transmission of electromagnetic energy from the signal feed structure to the leaky waveguide antenna section. The main innovation of this open waveguide antenna is the EM electromagnetic transition structure, where the waveguide transitions to a PCB transition to an open waveguide antenna. The antenna transition from waveguide to radiating structure requires a turning structure, but the slot of the turning structure is very small and difficult to manufacture, especially in the millimeter-wave band. Furthermore, the waveguide antenna uses a side-fed scheme, resulting in a large variation in the radiation pattern with frequency, leading to an asymmetrical radiation pattern.

[0004] Furthermore, the document "3653054 SYMMETRICAL TROUGH WAVEGUIDE ANTTENNA ARRAY RCACorporation Mar.28.1972 APPL .NP.84821" presents the radiation principle of an open waveguide antenna, but does not consider the antenna's fabrication and implementation, especially in the high-frequency range. The document "AN ELECTROMECHANTCALLY SCANNABLE TROUGH WAVEGUIDE ARRAY Air Force Cambridge Research Center Air Force And Development Command United States Air Force" presents the transmission and radiation principles of an open waveguide antenna, but also does not consider the antenna's fabrication and implementation, especially in the high-frequency range.

[0005] As can be seen from the existing technology, although the principle of open waveguides was discovered in the 1950s, it has mainly remained in the theoretical stage. To realize a physical object, especially in the millimeter wave band, significant innovations are needed in waveguide conversion, feed lines, and radiation. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a waveguide conversion structure for a LOP waveguide antenna, thereby realizing the application of waveguide conversion in a single-layer waveguide antenna in a LOP waveguide antenna.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A waveguide conversion structure for a LOP waveguide antenna includes an analog PCB board and a waveguide conversion structure body. The analog PCB board has four receiving ports and four transmitting ports. The waveguide conversion structure body has four upper waveguides and four lower waveguides. The four upper waveguides are located on the upper side of the waveguide conversion structure body, and the four lower waveguides are located on the lower side of the waveguide conversion structure body. One end of two upper waveguides and two lower waveguides is connected to the four receiving ports of the analog PCB board, and one end of the other two upper waveguides and two lower waveguides is connected to the four transmitting ports of the analog PCB board.

[0009] Furthermore, four analog ports are respectively provided on both sides of the waveguide conversion structure body. The other ends of the two upper waveguides and two lower waveguides connected to the four receiving ports are connected to the four analog ports on one side of the waveguide conversion structure body in a one-to-one correspondence. The other ends of the other two upper waveguides and two lower waveguides connected to the four transmitting ports are connected to the four analog ports on the other side of the waveguide conversion structure body in a one-to-one correspondence.

[0010] Furthermore, the lower waveguide includes a lower open waveguide, one end of which is connected to a port of the analog PCB board through a first third-order impedance matching.

[0011] Furthermore, the first third-order impedance matching includes a first-level impedance matching stub, a second-level impedance matching stub, and a third-level impedance matching stub located at the end of the intermediate spacer of the lower open waveguide. The first-level impedance matching stub, the second-level impedance matching stub, and the third-level impedance matching stub are arranged sequentially from the end of the intermediate spacer of the lower open waveguide to the other end.

[0012] Furthermore, the slot width of the lower-opening waveguide is 3.1 mm, the slot height of the lower-opening waveguide is 2.3 mm, the width of the middle spacer of the lower-opening waveguide is 0.6 mm, the height of the middle spacer of the lower-opening waveguide is 1.7 mm, the height of the first-stage impedance matching stub is 1.5 mm, the length of the first-stage impedance matching stub is 0.8 mm, the height of the second-stage impedance matching stub is 1.87 mm, the length of the second-stage impedance matching stub is 0.46 mm, the height of the third-stage impedance matching stub is 1.76 mm, and the length of the third-stage impedance matching stub is 0.8 mm.

[0013] Furthermore, the upper waveguide includes a transition groove, a transmission via, and an upper open waveguide. The transition groove is configured to correspond to the port of the simulated PCB board. The transmission via penetrates the waveguide conversion structure body to connect the transition groove and the upper open waveguide. One end of the upper open waveguide is connected to the transmission via through second- or third-order impedance matching. The transmission via is stepped in the length direction, and the length of the end of the transmission via connected to the transition groove is greater than the length of the other end.

[0014] Furthermore, the second and third order impedance matching includes a fourth-order impedance matching stub, a fifth-order impedance matching stub, and a sixth-order impedance matching stub located at the end of the intermediate spacer of the lower open waveguide. The fourth-order impedance matching stub, the fifth-order impedance matching stub, and the sixth-order impedance matching stub are arranged sequentially from the end of the intermediate spacer of the lower open waveguide to the other end.

[0015] Furthermore, the slot width of the upper open waveguide is 2.2 mm, the slot height of the upper open waveguide is 3.7 mm, the width of the middle spacer of the upper open waveguide is 0.6 mm, the height of the middle spacer of the upper open waveguide is 1.4 mm, the height of the fourth-level impedance matching stub is 0.37 mm, the length of the fourth-level impedance matching stub is 1 mm, the height of the fifth-level impedance matching stub is 0.62 mm, the length of the fifth-level impedance matching stub is 0.95 mm, the height of the sixth-level impedance matching stub is 1.02 mm, the length of the sixth-level impedance matching stub is 0.73 mm, the length of the end of the transmission via connected to the upper open waveguide is 2.2 mm, the width of the end of the transmission via connected to the upper open waveguide is 0.82 mm, the length of the end of the transmission via connected to the transition slot is 2.7 mm, the width of the end of the transmission via connected to the transition slot is 0.82 mm, the length of the transition slot is 7 mm, and the width of the transition slot is 1.9 mm.

[0016] Furthermore, a ring of pillars is provided on the outer side of the four receiving ports and four transmitting ports of the simulated PCB board, and a row of pillars is provided on both sides of the eight ports. The lower side of the waveguide conversion structure body is provided with pillars that correspond one-to-one with the pillars of the simulated PCB board. The pillars of the waveguide conversion structure body and the pillars of the simulated PCB board constitute an electromagnetic bandgap structure.

[0017] Furthermore, wave-blocking grooves are provided on both sides of the lower waveguide.

[0018] Compared with the prior art, the present invention has the following advantages and effects:

[0019] 1. This invention provides a waveguide transition structure for a LOP waveguide antenna, which adopts a transition slot and a vertical transition scheme for two signals to solve the problem of interference between adjacent ports, realizes the application of a single-layer waveguide antenna in a LOP waveguide antenna, and has the feasibility of mass production in the 77GHz operating frequency band.

[0020] 2. After the 4t4r waveguide conversion line of this invention is output, half of the channels are on the upper side of the waveguide and half of the channels are on the lower side of the waveguide. This can ensure flexible feeder design and make it easier to achieve equal phase design in the case of compact layout.

[0021] 3. This invention only requires one layer to realize the waveguide conversion of the Infineon 4T4R LOP port, while the traditional solution requires at least two layers. This reduces the number of antenna layers, lowers the cost of the antenna, reduces the number of antenna installations, and improves the yield rate.

[0022] 4. This invention designs an electromagnetic bandgap structure between the waveguide conversion structure body and the analog PCB board. No soldering is required during installation, and a certain gap is allowed without electromagnetic wave leakage, thereby improving yield. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the waveguide conversion structure of a LOP waveguide antenna according to the present invention.

[0024] Figure 2 This is a schematic diagram of the waveguide conversion structure body of the present invention.

[0025] Figure 3 This is a schematic diagram of the waveguide conversion structure body of the present invention from another angle.

[0026] Figure 4 This is a schematic diagram of the reverse side of the waveguide conversion structure body of the present invention.

[0027] Figure 5 This is a schematic diagram of the simulated PCB board of the present invention.

[0028] Figure 6 The above diagram shows the S-parameter simulation results of the upper and lower waveguides in an embodiment of the present invention.

[0029] Figure 7 This is a simulation result diagram of the gap tolerance of the lower waveguide in an embodiment of the present invention.

[0030] Figure 8This is a simulation result diagram of the gap tolerance of the upper waveguide in an embodiment of the present invention.

[0031] Figure 9 This is a comparison simulation result diagram of the lower waveguide with and without a wave-blocking groove in an embodiment of the present invention. Detailed Implementation

[0032] To illustrate in detail the technical solutions adopted by the present invention to achieve the intended technical objectives, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Furthermore, the technical means or technical features in the embodiments of the present invention can be replaced without creative effort. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0033] like Figure 1 As shown, a waveguide conversion structure for a LOP waveguide antenna according to the present invention includes an analog PCB board 1 and a waveguide conversion structure body 2, wherein the waveguide conversion structure body 2 is mounted on the upper side of the analog PCB board 1.

[0034] like Figure 5 As shown, the simulated PCB board 1 is provided with four receiving ports 3 and four transmitting ports 4. The eight ports are arranged in pairs in a row, with the two ports in each row arranged along the width direction of the simulated PCB board 1. The four rows of ports are distributed along the length direction of the simulated PCB board 1, with the four ports on the left being receiving ports 3 and the four ports on the right being transmitting ports 4.

[0035] like Figure 2 , 3As shown in Figure 4, the waveguide conversion structure body 2 is provided with four upper waveguides 5 and four lower waveguides 6. The four upper waveguides 5 are located on the upper side of the waveguide conversion structure body 2, and the four lower waveguides 6 are located on the lower side of the waveguide conversion structure body 2. One end of two upper waveguides 5 and two lower waveguides 6 are connected to the four receiving ports 3 of the analog PCB board 1, and one end of the other two upper waveguides 5 and two lower waveguides 6 are connected to the four transmitting ports 4 of the analog PCB board 1. Since the receiving and transmitting ports of the Infineon 4T4R port are distributed on both sides, four waveguides need to be connected on one side. The thickness of the analog PCB board 1 is 1.6mm, the size of the 8 ports is 0.8*2.74mm, the spacing between adjacent ports is (3mm, 0.5mm), and the width of the waveguide is more than 2mm. The size of the LOP port is insufficient to design and distribute the four waveguides on one side. To address this problem, this invention designs four waveguides on the same side as a two-layer structure. The waveguides at the two ports on the edge are designed on the lower side of the waveguide conversion structure body 2, while the waveguides at the two ports on the inner side are designed on the upper side of the waveguide conversion structure body 2. By employing a transition slot and a vertical transition scheme for the signal twice, the problem of interference between adjacent ports is solved, realizing the application of a single-layer waveguide antenna in a LOP waveguide antenna. It is feasible for mass production in the 77GHz operating frequency band.

[0036] Four analog ports 7 are respectively provided on both sides of the waveguide conversion structure body 2. The other ends of the two upper waveguides 5 and the two lower waveguides 6 connected to the four receiving ports 3 are connected to the four analog ports 7 on one side of the waveguide conversion structure body 2 in a one-to-one correspondence. The other ends of the other two upper waveguides 5 and the two lower waveguides 6 connected to the four transmitting ports 4 are connected to the four analog ports 7 on the other side of the waveguide conversion structure body 2 in a one-to-one correspondence.

[0037] Four upper waveguides 5 and four lower waveguides 6 are arranged along the width direction of the four receiving ports 3 and the four transmitting ports 4, respectively.

[0038] The lower waveguide 6 includes a lower open waveguide, one end of which is connected to port 7 of the analog PCB board 1 through a first-third-order impedance matching.

[0039] The first and third-order impedance matching includes a first-level impedance matching stub 8, a second-level impedance matching stub 9, and a third-level impedance matching stub 10 located at the end of the middle spacer of the lower open waveguide. The first-level impedance matching stub 8, the second-level impedance matching stub 9, and the third-level impedance matching stub 10 are arranged sequentially from the end of the middle spacer of the lower open waveguide to the other end.

[0040] The slot width of the lower-opening waveguide is 3.1 mm, the slot height of the lower-opening waveguide is 2.3 mm, the width of the middle spacer of the lower-opening waveguide is 0.6 mm, the height of the middle spacer of the lower-opening waveguide is 1.7 mm, the height of the first-stage impedance matching stub 8 is 1.5 mm, the length of the first-stage impedance matching stub 8 is 0.8 mm, the height of the second-stage impedance matching stub 9 is 1.87 mm, the length of the second-stage impedance matching stub 9 is 0.46 mm, the height of the third-stage impedance matching stub 10 is 1.76 mm, and the length of the third-stage impedance matching stub 10 is 0.8 mm.

[0041] The upper waveguide 5 includes a transition groove 11, a transmission via 12, and an upper open waveguide. The transition groove 11 is set to correspond to the port of the analog PCB board 1. The transmission via 12 passes through the waveguide conversion structure body 2 to connect the transition groove 11 and the upper open waveguide. One end of the upper open waveguide is connected to the transmission via 12 through second and third order impedance matching. The transmission via 12 is stepped in the length direction, and the length of the end of the transmission via 12 connected to the transition groove 11 is greater than the length of the other end.

[0042] The second and third order impedance matching includes a fourth-order impedance matching stub 13, a fifth-order impedance matching stub 14, and a sixth-order impedance matching stub 15 located at the end of the middle spacer of the lower open waveguide. The fourth-order impedance matching stub 13, the fifth-order impedance matching stub 14, and the sixth-order impedance matching stub 15 are arranged sequentially from the end of the middle spacer of the lower open waveguide to the other end.

[0043] The slot width of the upper-opening waveguide is 2.2 mm, the slot height is 3.7 mm, the width of the middle spacer of the upper-opening waveguide is 0.6 mm, the height of the middle spacer of the upper-opening waveguide is 1.4 mm, the height of the fourth-stage impedance matching stub 13 is 0.37 mm, the length of the fourth-stage impedance matching stub 13 is 1 mm, the height of the fifth-stage impedance matching stub 14 is 0.62 mm, the length of the fifth-stage impedance matching stub 14 is 0.95 mm, and the sixth-stage impedance matching stub 1... The height of section 5 is 1.02 mm, the length of the sixth-stage impedance matching stub 15 is 0.73 mm, the length of the end of the transmission via 12 connected to the upper open waveguide is 2.2 mm, the width of the end of the transmission via 12 connected to the upper open waveguide is 0.82 mm, the length of the end of the transmission via 12 connected to the transition groove 11 is 2.7 mm, the width of the end of the transmission via 12 connected to the transition groove 11 is 0.82 mm, the length of the transition groove 11 is 7 mm, and the width of the transition groove 11 is 1.9 mm.

[0044] The four receiving ports 3 and four transmitting ports 4 of the analog PCB board 1 are each surrounded by a ring of pillars 16. A row of pillars 16 is also provided on both sides of the eight ports. The lower side of the waveguide conversion structure body 2 is provided with pillars 16 that correspond one-to-one with the pillars of the analog PCB board 1. The pillars of the waveguide conversion structure body 2 and the pillars of the analog PCB board 1 form an electromagnetic bandgap structure. No soldering is required during installation, and a certain gap is allowed without electromagnetic wave leakage, thus improving the yield.

[0045] Wave-blocking grooves 17 are provided on both sides of the lower waveguide 6. One end of the wave-blocking groove 17 is located on the side of the waveguide conversion structure body 2, and the other end of the wave-blocking groove 17 is close to the electromagnetic bandgap structure. The wave-blocking groove can effectively reduce the height of the waveguide on this side and allow a certain gap without sound leakage. The lower waveguide combined with the wave-blocking groove can significantly reduce the height of the channel and improve the tolerance of the gap, while improving the feasibility of processing and increasing the yield.

[0046] like Figure 6 As shown, S11 is the return loss of the lower waveguide, S21 is the transmission coefficient of the lower waveguide, S33 is the return loss of the upper waveguide, and S43 is the transmission coefficient of the upper waveguide. Since the lower waveguide undergoes only one vertical signal transition, the antenna's transmission coefficient is less than 0.1 dB and VSWR is less than -22 dB in the 76-79 GHz band, and less than 0.5 dB and VSWR is less than -11 dB in the 76-81 GHz band. The upper waveguide undergoes two vertical signal transitions, resulting in a transmission coefficient of less than 0.4 dB and VSWR of less than -24 dB in the 76-79 GHz band, and less than 0.9 dB and VSWR of less than -10 dB in the 76-81 GHz band.

[0047] Figure 6 The simulation results are when the gap between the pillar of the waveguide conversion structure body 2 and the pillar of the simulated PCB board 1 is 0. However, considering that there is a certain gap between the actual antenna and the PCB, a certain tolerance performance of the waveguide conversion needs to be considered. Figure 7 and Figure 8 The figures show the simulation results for the gap tolerance of the lower and upper waveguides, respectively. With a gap of less than 0.2mm in the lower waveguide, the antenna can operate in the 76-81GHz frequency band, with a transmission coefficient less than 0.6dB. With a gap of less than 0.2mm in the upper waveguide, the antenna can operate in the 76-79GHz frequency band, with a transmission coefficient less than 0.7dB. Although the transmission coefficient drops significantly in the 79-81GHz range when the gap is greater than 0.1mm, this is due to the deterioration of the standing wave ratio. Electromagnetic wave leakage is less; further bandwidth optimization can ensure a wider operating frequency band for the antenna. If screws are used for mounting near the port, the waveguide converter can be guaranteed to operate within the 76-81GHz frequency band.

[0048] like Figure 9 As shown, the port length of the lower waveguide is increased by 4mm, and the gap between the waveguide conversion structure body and the analog PCB board is set to 0.1mm. Figure 9 Comparative simulations revealed a 0.4 dB difference in the transmission coefficient of antennas within the 76-79 GHz operating frequency band, demonstrating that wave-blocking grooves significantly reduce electromagnetic wave leakage. Without wave-blocking grooves, the channel thickness would need to be increased; wave-blocking grooves can reduce the channel thickness by about one-third, improving the feasibility of fabrication and mass production.

[0049] This invention provides a waveguide conversion structure for a LOP waveguide antenna, employing a transition slot and a two-stage vertical signal transition scheme to solve the problem of interference between adjacent port outputs. This enables the application of a single-layer waveguide antenna in a LOP waveguide antenna, and demonstrates feasibility for mass production in the 77GHz operating frequency band. After the 4t4r waveguide conversion, half of the channels are on the upper side of the waveguide, and half are on the lower side, ensuring flexible feeder design and facilitating equal-phase design even with a compact layout. This invention requires only one layer to achieve waveguide conversion for Infineon's 4t4r LOP ports, while traditional solutions require at least two layers, reducing the number of antenna layers, lowering antenna cost, reducing the number of antenna installations, and improving yield. Furthermore, this invention incorporates an electromagnetic bandgap structure between the waveguide conversion structure and the analog PCB board, eliminating the need for soldering during installation and allowing for a certain gap without electromagnetic wave leakage, further improving yield.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A waveguide conversion structure for a LOP waveguide antenna, characterized in that: It includes a simulated PCB board and a waveguide conversion structure body. The simulated PCB board is equipped with four receiving ports and four transmitting ports. The waveguide conversion structure body is equipped with four upper waveguides and four lower waveguides. The four upper waveguides are located on the upper side of the waveguide conversion structure body, and the four lower waveguides are located on the lower side of the waveguide conversion structure body. One end of two upper waveguides and two lower waveguides are connected to the four receiving ports of the simulated PCB board, and one end of the other two upper waveguides and two lower waveguides are connected to the four transmitting ports of the simulated PCB board. The lower waveguide includes a lower open waveguide, one end of which is connected to the port of the analog PCB board through a first third-order impedance matching; the first third-order impedance matching includes a first-level impedance matching stub, a second-level impedance matching stub, and a third-level impedance matching stub located at the end of the middle spacer of the lower open waveguide, and the first-level impedance matching stub, the second-level impedance matching stub, and the third-level impedance matching stub are arranged sequentially from the end of the middle spacer of the lower open waveguide to the other end; The upper waveguide includes a transition slot, a transmission via, and an upper open waveguide. The transition slot is configured to correspond to the port of the simulated PCB board. The transmission via penetrates the waveguide conversion structure body to connect the transition slot and the upper open waveguide. One end of the upper open waveguide is connected to the transmission via through a second- or third-order impedance matching. The transmission via is stepped in the length direction, and the length of the end of the transmission via connected to the transition slot is greater than the length of the other end. The second- or third-order impedance matching includes a fourth-order impedance matching stub, a fifth-order impedance matching stub, and a sixth-order impedance matching stub located at the end of the middle spacer of the lower open waveguide. The fourth-order impedance matching stub, the fifth-order impedance matching stub, and the sixth-order impedance matching stub are sequentially arranged along the end of the middle spacer of the lower open waveguide to the other end.

2. The waveguide conversion structure of a LOP waveguide antenna according to claim 1, characterized in that: The waveguide conversion structure body has four analog ports on each side. The other ends of the two upper waveguides and two lower waveguides connected to the four receiving ports are connected to the four analog ports on one side of the waveguide conversion structure body. The other ends of the other two upper waveguides and two lower waveguides connected to the four transmitting ports are connected to the four analog ports on the other side of the waveguide conversion structure body.

3. The waveguide conversion structure of a LOP waveguide antenna according to claim 1, characterized in that: The slot width of the lower-opening waveguide is 3.1 mm, the slot height of the lower-opening waveguide is 2.3 mm, the width of the middle spacer of the lower-opening waveguide is 0.6 mm, the height of the middle spacer of the lower-opening waveguide is 1.7 mm, the height of the first-stage impedance matching stub is 1.5 mm, the length of the first-stage impedance matching stub is 0.8 mm, the height of the second-stage impedance matching stub is 1.87 mm, the length of the second-stage impedance matching stub is 0.46 mm, the height of the third-stage impedance matching stub is 1.76 mm, and the length of the third-stage impedance matching stub is 0.8 mm.

4. The waveguide conversion structure of a LOP waveguide antenna according to claim 1, characterized in that: The upper-opening waveguide has a slot width of 2.2 mm, a slot height of 3.7 mm, a middle spacer width of 0.6 mm, a middle spacer height of 1.4 mm, a fourth-stage impedance matching stub height of 0.37 mm, a fourth-stage impedance matching stub length of 1 mm, a fifth-stage impedance matching stub height of 0.62 mm, a fifth-stage impedance matching stub length of 0.95 mm, a sixth-stage impedance matching stub height of 1.02 mm, and a sixth-stage impedance matching stub length of 0.73 mm. The transmission via connected to the upper-opening waveguide has a length of 2.2 mm and a width of 0.82 mm. The transmission via connected to the transition slot has a length of 2.7 mm and a width of 0.82 mm. The transition slot has a length of 7 mm and a width of 1.9 mm.

5. The waveguide conversion structure of a LOP waveguide antenna according to claim 1, characterized in that: The simulated PCB board has a ring of pillars on the outside of its four receiving ports and four transmitting ports, and a row of pillars on both sides of each of the eight ports. The waveguide conversion structure body has pillars on its lower side that correspond one-to-one with the pillars of the simulated PCB board. The pillars of the waveguide conversion structure body and the pillars of the simulated PCB board together form an electromagnetic bandgap structure.

6. The waveguide conversion structure of a LOP waveguide antenna according to claim 1, characterized in that: Wave-blocking grooves are provided on both sides of the lower waveguide.

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