High-isolation plastic metallization waveguide slot antenna

Abstract

A high-isolation plastic metallization waveguide slot antenna disclosed by the present invention comprises a fixed backboard, and a transmitting antenna, a transmit-receive isolation structure and a receiving antenna which are arranged on the fixed backboard, the transmitting antenna comprises a waveguide slot antenna unit and is used for transmitting an electromagnetic signal, the transmit-receive isolation structure is arranged between the transmit-receive antennas, and the transmit-receive antenna is used for transmitting the electromagnetic signal. And the receiving antenna is used for suppressing spatial wave coupling between the transmitting antenna and the receiving antenna, and the receiving antenna comprises eight waveguide slot antenna units which are arranged according to preset positions and is used for receiving echo signals of a target. While the gain requirement is ensured, the antenna has the characteristic of high isolation, and has the advantages of light weight and low cost.

Description

Technical Field

[0001] The invention belongs to antenna technology, in particular to a high-isolation plastic metallized waveguide slot antenna. Background Art

[0002] Plastic metallized antennas achieve antenna functions by electroplating on the plastic surface. Compared with traditional metal antennas, plastic metallized antennas have the advantages of being able to combine precision injection molding technology, high processing accuracy, one-time molding, light weight, good consistency, improving the overall reliability of the antenna, and reducing overall costs. The use of plastic metallized materials makes it easier to achieve lightweight, low-cost, and mass production of waveguide array antennas.

[0003] Waveguide slot antenna refers to an antenna formed by etching various slots on the waveguide. Commonly used slots are longitudinal slots on the wide side of the waveguide, inclined slots on the narrow side, and transverse slots on the wide side. Waveguides can shield electromagnetic fields. When various slots are etched on the metal wall of the waveguide, these slots can couple energy through the field inside the waveguide. Main mode TE 10 The current can be divided into two components, the transverse component and the longitudinal component. The transverse component presents a cosine distribution along the wide metal wall of the waveguide, and reaches the maximum value at the center; there is only transverse current on the narrow metal wall, which is evenly distributed. When the direction of the slot forms a certain angle with the direction of the current line, the current line will be cut by the slot on the metal wall, the transmission of the current line will be interrupted, and the current will continue to be transmitted as a displacement current. In this way, the slot can be excited and radiate electromagnetic waves.

[0004] Due to the characteristics of compact structure, high radiation efficiency and easy control of aperture amplitude distribution, waveguide slot antennas are widely used in shipborne, missile-borne radars, navigation and other radar systems and microwave communications.

[0005] Reference 1 (A. Garcia-Tejero, M. Burgos-Garcia and F. Merli, "Broadband Metalized Plastic Waveguide Antenna with Robust Isolation Interface at 77GHz," in IEEE Antennas and Wireless Propagation Letters.) designed a plastic metalized waveguide antenna for 76-81GHz automotive radar. The antenna includes three transmitting antennas and four receiving antennas. Each antenna unit includes 8 linearly arranged units. The whole is made by injection molding, metallization and welding processes, and the impedance bandwidth is 20.1%. Compared with the traditional antenna based on dielectric substrate, this design and manufacturing method has the advantages of low cost and high precision. Reference 2 (L. Ma, M. Li, P. Chen, H. Zhang and X. Yu, "esign of Low Sidelobe Waveguide Slot Antenna Arrays," 2020 13th UK-Europe-China Workshop on Millimetre-Waves and Terahertz Technologies (UCMMT), Tianjin, China, 2020, pp. 1-3.) proposes a slot waveguide array antenna for radar target detection with an operating frequency of 15.14-15.24 GHz. The antenna array consists of four side-by-side 32-slot waveguide slot antennas, which are fed by a 1-to-8 waveguide power divider. The antenna array has a high gain of 27 dB and a low sidelobe of -24 dB, but the antenna is made of metal material as a whole, which has the disadvantages of heavy weight and high insertion loss compared to plasticized metal. Summary of the invention

[0006] The purpose of the present invention is to provide a high-isolation plastic metallized waveguide slot antenna.

[0007] The technical solution for achieving the purpose of the present invention is: a high-isolation plastic metallized waveguide slot antenna, comprising a fixed backplane and a transmitting antenna, a transceiver isolation structure, and a receiving antenna arranged on the fixed backplane, wherein the transmitting antenna comprises a waveguide slot antenna unit for transmitting electromagnetic signals, the transceiver isolation structure is placed between the transceiver antennas for suppressing spatial wave coupling between the transmitting antenna and the receiving antenna, and the receiving antenna comprises 8 waveguide slot antenna units arranged according to predetermined positions for receiving the echo signal of the target.

[0008] Preferably, the waveguide slot antenna unit includes: a waveguide structure, a coaxial-to-waveguide structure and a coaxial probe. The bottom surface of the waveguide structure is connected to the coaxial-to-waveguide structure, and the coaxial probe extends from the bottom surface of the coaxial-to-waveguide structure. The top surface of the coaxial-to-waveguide structure is provided with two waveguide slot antenna radiation slots parallel to the wide side of the waveguide structure. Inside the coaxial-to-waveguide structure, a square ridge is provided on both sides of each waveguide slot antenna radiation slot.

[0009] Preferably, the coaxial-to-waveguide structure is an L-shaped structure.

[0010] Preferably, the radiation slots of the two waveguide slot antennas are 26 mm in length, 4 mm in width and 2.5 mm in depth.

[0011] Preferably, the transceiver isolation structure is a plastic metallized isolation wall with a choke slot of a preset size.

[0012] Preferably, the transceiver isolation structure includes a first rectangle and a second rectangle, and the first rectangle and the second rectangle form a T-shaped wall; three choke slots parallel to the long sides are etched in the middle of the first rectangle, and three choke slots parallel to the long sides of the rectangle are etched in the middle of the second rectangle.

[0013] Preferably, the distance between adjacent choke slots is 25 mm, the depth of the choke slots is 16 mm, and the width is 20 mm.

[0014] Preferably, with the transmitting antenna as the coordinate origin, the slot direction of the parallel waveguide as the x direction, the vertical slot direction as the y direction, and 1 wavelength λ as a unit, the positions of the eight receiving antennas are (0.5λ, 5λ), (1.5λ, 5λ), (3λ, 5λ), (4.5λ, 5λ), (5λ, 5λ), (5.5λ, 4.5λ), (5λ, 3.5λ), and (5λ, 0.5λ).

[0015] Compared with the prior art, the present invention has the following significant advantages: the present invention adopts plastic metallized material, has low loss, low cost, light weight, and is easy to mass produce. The waveguide antenna adopts narrow-side slots and alternately arranges square ridges on both sides of the slots to reduce cross polarization and improve the radiation efficiency of the waveguide slot antenna. An isolation structure is designed between the receiving antenna and the transmitting antenna to effectively reduce the spatial wave coupling effect and achieve high isolation between the transmitting and receiving antennas.

[0016] The present invention is described in further detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the three-dimensional structure of a high-isolation plastic metallized waveguide slot antenna.

[0018] Figure 2 Schematic diagram of a waveguide slot antenna unit.

[0019] Figure 3 Schematic diagram of the isolation structure of the present invention.

[0020] Figure 4 A top view of the waveguide slot antenna unit.

[0021] Figure 5 It is a cross-sectional schematic diagram of an embodiment of the high-isolation plastic metallized waveguide slot antenna unit of the present invention.

[0022] Figure 6 The cross-sectional schematic diagram is a schematic diagram of an embodiment of the coaxial-to-waveguide structure of the high-isolation plastic metallized waveguide slot antenna unit of the present invention.

[0023] Figure 7 It is a top plan view of an embodiment of the high isolation plastic metallized waveguide slot antenna isolation structure of the present invention.

[0024] Figure 8 It is a side view of an embodiment of the high-isolation plastic metallized waveguide slot antenna isolation structure of the present invention.

[0025] Fig. 9 It is the return loss of the high isolation plastic metallized waveguide slot antenna of the present invention.

[0026] Fig.10 It is the transmit-receive isolation of the high-isolation plastic metallized waveguide slot antenna of the present invention.

[0027] Fig.11 The azimuth antenna radiation pattern of the high-isolation plastic metallized waveguide slot antenna of the present invention.

[0028] Fig.12 This is the elevation antenna radiation pattern of the high-isolation plastic metallized waveguide slot antenna of the present invention. DETAILED DESCRIPTION

[0029] like Figures 1 to 8 As shown, a high-isolation plastic metallized waveguide slot antenna comprises a fixed back plate (4) and a transmitting antenna (1), a transceiver isolation structure (2), and a receiving antenna (3) arranged on the fixed back plate (4), wherein the transmitting antenna (1) comprises a waveguide slot antenna unit for transmitting electromagnetic signals, the transceiver isolation structure is arranged between the transceiver antennas for suppressing spatial wave coupling between the transmitting antenna (1) and the receiving antenna (3), and the receiving antenna (3) comprises 8 waveguide slot antenna units arranged according to predetermined positions for receiving echo signals of a target. The waveguide slot antenna unit is composed of metallized plastic and is manufactured by injection molding, electroplating and welding processes.

[0030] In a further embodiment, the waveguide slot antenna unit comprises: a waveguide structure (14), a coaxial-to-waveguide structure (13) and a coaxial probe, the bottom surface of the waveguide structure (14) is connected to the coaxial-to-waveguide structure (13), the coaxial probe extends from the bottom surface of the coaxial-to-waveguide structure (13), the top surface of the coaxial-to-waveguide structure (13) is provided with two waveguide slot antenna radiation slots (11) parallel to the wide side of the waveguide structure, and inside the coaxial-to-waveguide structure (13), each waveguide slot antenna radiation slot (11) is provided with a square ridge (12) on both sides. The position of the waveguide slot antenna radiation slot (11) is used to control the antenna radiation amplitude phase distribution, and the square ridges (12) on both sides of the waveguide slot antenna radiation slot (11) are used to change the excitation current in the waveguide, reduce the cross polarization between the slot units, and improve the radiation efficiency of the waveguide slot antenna.

[0031] Specifically, the spacing of the radiation slots (11) of the waveguide slot antenna is d1, the length is L3, the width is W3, and the depth is t3.

[0032] Specifically, there are four square ridges, one on each side of each waveguide slot antenna radiation slot (11), and the two square ridges on both sides of the waveguide slot antenna radiation slot (11) are located at diagonal positions of the slot, close to the inner wall of the wide side of the waveguide, and the distance from the edge of the waveguide slot antenna radiation slot (11) is 0.5 mm. The function of the square ridges is to change the excitation current in the waveguide and improve the radiation efficiency of the waveguide slot antenna.

[0033] In a further embodiment, the transmitting antenna is taken as the coordinate origin, the slot direction of the parallel waveguide is taken as the x direction, the vertical slot direction is taken as the y direction, and 1 wavelength λ is taken as a unit, and the positions of the eight receiving antennas are respectively (0.5λ, 5λ), (1.5λ, 5λ), (3λ, 5λ), (4.5λ, 5λ), (5λ, 5λ), (5.5λ, 4.5λ), (5λ, 3.5λ), and (5λ, 0.5λ).

[0034] Furthermore, the waveguide slot antenna unit has a length of L1, a width of W1, a height of H1, and a thickness of t1.

[0035] In a further embodiment, the isolation structure is a plastic metallized isolation wall with etched choke slots,

[0036] Specifically, the isolation structure is composed of a T-shaped wall consisting of a first rectangle (21) with a length of 150 mm and a width of 110 mm and a second rectangle (22) with a length of 230 mm and a width of 105 mm, and the overall height of the T-shaped wall is 90 mm. A total of 6 rectangular choke slots of the same width are etched on the upper surface of the isolation wall, wherein three choke slots parallel to the long sides of the rectangle are etched in the middle of the first rectangle (21), and the three choke slots are arranged linearly. Three choke slots parallel to the long sides of the rectangle are etched in the middle of the second rectangle (22), and the three choke slots are arranged linearly.

[0037] The length of the isolation structure is L2, the width is W2, the height is H2, and the width of the choke slot is W t , with a depth of t2, located between the transmitting and receiving antennas to suppress the coupling effect between the antennas and improve the isolation between the receiving antenna and the transmitting antenna.

[0038] Specifically, the square ridges in the waveguide are arranged alternately on both sides of the slot, with a distance d2 from the slot and a side length a. Their function is to change the excitation current in the waveguide, reduce the cross polarization between the radiation slots, and improve the overall radiation efficiency of the antenna.

[0039] Specifically, the coaxial probe extends from the bottom surface of the coaxial waveguide structure (13) into the probe with a radius of R1, the probe extends into the interior of the waveguide with a length of L4, and the distance from the short-circuit surface of the waveguide is d3.

[0040] The present invention reduces the return loss of the waveguide slot antenna by optimizing the width W3 and depth t3 of the waveguide slot, the length L4 of the coaxial probe extending into the waveguide, and the distance d3 between the probe and the waveguide short-circuit surface; improves the antenna radiation pattern by optimizing the square ridge side length a on both sides of the slot in the waveguide and the slot unit spacing d1. By optimizing the height H2 of the isolation structure and the depth t2 of the choke slot, the spatial coupling effect of the transmitting and receiving antennas is reduced, and the isolation between the transmitting and receiving antennas is improved.

[0041] In some embodiments, the values ​​of the parameters are shown in Table 1:

[0042] Table 1

[0043]

[0044] The present invention reduces the return loss of the waveguide slot antenna by optimizing the width W3 and depth t3 of the waveguide slot, the length L4 of the coaxial probe extending into the waveguide, and the distance d3 between the probe and the waveguide short-circuit surface; improves the antenna radiation pattern by optimizing the square ridge side length a on both sides of the slot in the waveguide and the slot unit spacing d1. By optimizing the height H2 of the isolation structure and the depth t2 of the choke slot, the spatial coupling effect of the transmitting and receiving antennas is reduced, and the isolation between the transmitting and receiving antennas is improved.

[0045] The present invention will be further explained below in conjunction with the embodiments.

[0046] Example 1

[0047] like Figure 1 As shown, a high-isolation plastic metallized waveguide slot antenna of this embodiment includes a transmitting antenna, a receiving antenna, an isolation structure and a fixed backplane. The transmitting antenna is composed of one waveguide slot antenna unit, the receiving antenna is composed of eight waveguide slot antenna units, the isolation structure is a plasticized metal wall with a preset size choke slot, located between the transmitting and receiving antennas, and used to improve the isolation between the receiving antenna and the transmitting antenna, and the fixed backplane is an aluminum alloy flat plate, which is used to fix the transmitting antenna, the receiving antenna and the isolation structure. The waveguide slot antenna unit is composed of metallized plastic and is manufactured by injection molding, electroplating and welding processes.

[0048] The return loss of the waveguide slot antenna is reduced by optimizing the width W3 and depth t3 of the slot of the waveguide slot antenna unit, the length L4 of the probe of the coaxial-to-waveguide structure, and the distance d3 from the waveguide short-circuit surface; the beam width of the slot waveguide antenna is optimized by optimizing the slot unit spacing d1; the isolation structure is a plastic metallized isolation wall with linearly arranged choke grooves etched thereon, and the spatial wave coupling between the receiving antenna and the transmitting antenna is suppressed by optimizing the isolation wall height H2 and the choke groove depth t2, thereby improving the isolation between the transmitting and receiving antennas.

[0049] The simulation software HFSS is used to simulate and optimize the entire antenna, and the simulation results of the high-isolation plastic metallized waveguide slot antenna are obtained.

[0050] This embodiment simulates a high-isolation plastic metallized waveguide slot antenna. Fig. 9 As shown in the figure, the antenna return loss is less than -10dB at 5.26GHz-5.65GHz. Fig.10 As shown in the figure, the isolation between the receiving antenna and the transmitting antenna at the 5.5 GHz frequency point is 67 dB, 68 dB, 68 dB, 68 dB, 69 dB, 70 dB, 71 dB, and 80 dB respectively. Figures 11-12 As shown, the operating frequency of the high isolation plastic metallized waveguide slot antenna is 5.5 GHz, the antenna gain is 9.6 dB, the 3 dB beam width in the elevation plane is 35°, and the 3 dB beam width in the horizontal plane is 84°.

Claims

1. A high isolation plastic metallized waveguide slot antenna, characterized in that: The invention comprises a fixed back plate (4) and a transmitting antenna (1), a transmitting-receiving isolation structure (2), and a receiving antenna (3) arranged on the fixed back plate (4), wherein the transmitting antenna (1) comprises a waveguide slot antenna unit for transmitting electromagnetic signals, the transmitting-receiving isolation structure is arranged between the transmitting-receiving antennas and is used to suppress spatial wave coupling between the transmitting antenna (1) and the receiving antenna (3), and the receiving antenna (3) comprises eight waveguide slot antenna units arranged according to predetermined positions and is used to receive echo signals of a target.

2. The high isolation plastic metallized waveguide slot antenna according to claim 1, characterized in that: The waveguide slot antenna unit comprises: a waveguide structure (14), a coaxial-to-waveguide structure (13) and a coaxial probe; the bottom surface of the waveguide structure is connected to the coaxial-to-waveguide structure (13); the coaxial probe extends from the bottom surface of the coaxial-to-waveguide structure (13); the top surface of the waveguide structure (14) is provided with two waveguide slot antenna radiation slots (11) parallel to the narrow side of the waveguide structure; inside the waveguide structure (14), a square ridge (12) is provided on both sides of each waveguide slot antenna radiation slot (11).

3. The high isolation plastic metallized waveguide slot antenna according to claim 2, characterized in that: The coaxial waveguide structure (13) is an L-shaped structure.

4. The high isolation plastic metallized waveguide slot antenna according to claim 2, characterized in that: The two waveguide slot antenna radiation slots (11) have a length of 26 mm, a width of 4 mm and a depth of 2.5 mm.

5. The high isolation plastic metallized waveguide slot antenna according to claim 1, characterized in that: The transceiver isolation structure is a plastic metallized isolation wall with a choke slot of a preset size.

6. The high isolation plastic metallized waveguide slot antenna according to claim 1 or 5, characterized in that: The transceiver isolation structure comprises a first rectangle (21) and a second rectangle (22), wherein the first rectangle (21) and the second rectangle (22) form a T-shaped wall; three choke slots parallel to the long sides are etched in the middle of the first rectangle (21), and three choke slots parallel to the long sides of the rectangle are etched in the middle of the second rectangle (22).

7. The high isolation plastic metallized waveguide slot antenna according to claim 6, characterized in that: The distance between adjacent choke slots is 25mm, the depth of the choke slots is 16mm, and the width is 20mm.

8. The high isolation plastic metallized waveguide slot antenna according to claim 1, characterized in that: Taking the transmitting antenna as the coordinate origin, the slot direction parallel to the waveguide as the x direction, the direction perpendicular to the slot as the y direction, and one wavelength λ as the unit, the positions of the eight receiving antennas are (0.5λ, 5λ), (1.5λ, 5λ), (3λ, 5λ), (4.5·, 5λ), (5λ, 5λ), (5.5λ, 4.5λ), (5λ, 3.5λ), and (5λ, 0.5λ).

9. The high isolation plastic metallized waveguide slot antenna according to claim 1, characterized in that: The radius of the coaxial probe is 0.35 mm, the length of the coaxial probe inserted into the coaxial waveguide structure (13) is 14 mm, the metal probe is located at the center of the wide side of the coaxial waveguide structure (13) and is 7 mm away from the short-circuit surface of the coaxial waveguide structure (13).

10. The high isolation plastic metallized waveguide slot antenna according to claim 1, characterized in that: The height of the transceiver isolation structure is 90 mm.

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