Ka-band low-cost dual-circularly-polarized wide-angle scanning microstrip array antenna

Abstract

The invention discloses a Ka-band low-cost dual-circularly-polarized wide-angle scanning microstrip array antenna, and belongs to the field of mechanical auxiliary scanning antenna arrays. The antenna comprises a lower-layer metal plate, a dielectric layer and an upper-layer metal plate, wherein the lower-layer metal plate is provided with a feed network, the dielectric layer comprises a dielectric disc located in the middle and two dielectric substrate slab waveguides symmetrically arranged on the left side and the right side of the dielectric disc, and the dielectric disc is used for achieving dual-circular polarization radiation and can rotate to achieve mechanical auxiliary scanning; and the upper metal plate is used for fixing the dielectric layer and is provided with a circular through hole for placing and shielding the radiation opening surface. The antenna solves the problems that polarization of a traditional VICTS antenna design is linear polarization, the influence of multipath interference is large, satellite communication is not facilitated, beam coverage of a traditional Pillbox antenna design is limited, and the scanning angle is large, and has the advantages of being wide in beam scanning range, circular in polarization, low in profile and low in cost.

Description

Technical Field

[0001] The invention belongs to the field of mechanically assisted scanning antenna arrays, and relates to large-angle scanning and dual circular polarization antenna arrays, specifically left-hand circular polarization and right-hand circular polarization are respectively applied to left-feed port antennas and right-feed port antennas. Background Art

[0002] Vehicle-mounted satellite communications require an antenna solution with a wide beam scanning range, circular polarization, low profile and low cost. In satellite communications, circularly polarized waves are less affected by multipath effects and polarization distortion, and there are no strict requirements for the placement of receiving antennas. Therefore, circularly polarized antennas are generally used in satellite communication systems. Dual circular polarization can adapt to a variety of signal polarizations, avoid the problem of difficult signal reception, and effectively improve the channel capacity of the system by providing two orthogonal polarization modes. Compared with single circular polarization antennas, dual circular polarization antennas have greater advantages in satellite communications.

[0003] Advanced electronically scanned phased arrays have the characteristics of large-angle scanning and low profile, but the cost is relatively high; mechanical scanning is a lower-cost option, but the three-dimensional profile is high and the scanning speed is slow. Therefore, planar mechanical assisted scanning, which combines the advantages of electronically scanned phased arrays and mechanical scanning, has become an ideal low-profile, low-cost solution.

[0004] Common planar mechanical assisted scanning antennas include planar lens antennas, Pillbox antennas, and VICTS antennas. Planar lens antennas are end-fire antennas, so they are not suitable as vehicle-mounted satellite communication antennas. Pillbox antennas have a lower profile, which is more conducive to integration and suitable for multi-polarization design, but their scanning angles are usually less affected by the metal box and cannot be scanned continuously, so the antenna beam coverage is small. The VICTS antenna has the characteristic of continuous large-angle scanning, but its overall profile is very high due to the separation of the radiation layer and the feed layer, which is not conducive to integration on the roof, and traditional VICTS antennas are mostly linearly polarized or single-polarized, which are not suitable for multi-polarization design. Summary of the invention

[0005] Aiming at the problem that the polarization of traditional VICTS antenna design is linear polarization, which is greatly affected by multipath interference and is not conducive to satellite communication, and the beam coverage of traditional Pillbox antenna design is limited and the scanning angle is small. The present invention provides a dual circular polarization large angle scanning low-cost microstrip antenna working in Ka. The antenna works at 27.0GHz-31.0GHz and can fully meet the working needs of Ka-band low-orbit satellite communication and mobile communication.

[0006] The specific technical solution adopted by the present invention is as follows:

[0007] A dual circular polarization large angle scanning low-cost microstrip antenna working at Ka, characterized in that the antenna is left-right mirror symmetric, and comprises a lower metal plate, a dielectric layer, and an upper metal plate arranged in sequence from bottom to top;

[0008] The lower metal plate is provided with a feeding network, including two feeding branches symmetrically arranged on the left and right sides, and the two feeding branches are used to convert the input signal into a Quasi-TEM mode and feed it to the input ports of the dielectric substrate planar waveguide on the left and right sides respectively; at the same time, the upper surface of the lower metal plate is provided with a groove matching the shape of the dielectric layer, which is used to accommodate and fix the dielectric layer.

[0009] The dielectric layer includes a dielectric disk located in the middle and two dielectric substrate planar waveguides symmetrically arranged on the left and right sides of the dielectric disk; wherein the dielectric substrate planar waveguide is used to transmit the fed Quasi-TEM mode to the dielectric disk; the dielectric disk is used to realize circularly polarized radiation, when the dielectric disk receives the Quasi-TEM mode of the left feeding branch, right-hand circular polarization is realized, and when the dielectric disk receives the Quasi-TEM mode of the right feeding branch, left-hand circular polarization is realized, and at the same time, the dielectric disk can rotate left and right under external drive, thereby changing the beam direction and realizing mechanical auxiliary scanning.

[0010] The upper metal plate is used for pressing and fixing the dielectric layer, and a circular through hole is arranged in the central region thereof, the radius of which is smaller than the radius of the direct disk and larger than the radiation opening of the dielectric disk.

[0011] Preferably, the dielectric disk comprises a circular dielectric substrate and copper-clad layers on its upper and lower surfaces, wherein a radiation structure is arranged in the middle of the copper-clad layer on the upper surface; the radiation structure comprises a plurality of microstrip transmission lines arranged in parallel, and a plurality of radiation units; the radiation units are arranged in a triangular grid, and each radiation unit is composed of four rectangular radiation patches located on both sides of the microstrip transmission line, each rectangular radiation patch has a vertex connected to the microstrip transmission line, and the spacing between the vertex angles along the direction of electromagnetic wave travel is one-quarter of the working wavelength, and the rectangular radiation patches are rotated 90° in sequence to achieve dual circular polarization.

[0012] Preferably, a U-shaped groove is provided in the middle of the radiation patch to reduce the volume of the radiation patch.

[0013] Preferably, trapezoidal transition structures are provided at both ends of the microstrip transmission line to optimize matching.

[0014] Preferably, the dielectric substrate planar waveguide comprises a dielectric substrate and copper clad layers on its upper and lower surfaces, the outer side of the dielectric substrate is arc-shaped, the inner side is semicircular, and a stepped structure is provided along the electromagnetic wave transmission direction; an arc-shaped groove matching the shape of the output port of the feeding network is etched on the outer edge of the copper clad layer on the lower surface of the dielectric substrate, serving as the input port of the dielectric substrate planar waveguide, and the output port of the dielectric substrate planar waveguide is a cylindrical surface close to the dielectric disk.

[0015] Preferably, the feeding network is divided into two parts, the left part includes a step-matching waveguide, a planar horn, a trapezoidal planar waveguide, and a plane wave transition structure, and the right part is mirror-symmetrical to the left part; wherein the step-matching waveguide is vertically arranged, and its input port is a standard waveguide port and is located at the bottom of the lower metal plate, for feeding the input signal into the planar horn; the planar horn is transversely arranged in the lower metal plate, for converting the input signal into a TE10 mode and feeding it into the trapezoidal planar waveguide; the trapezoidal planar waveguide is transversely arranged in the lower metal plate, for converting the TE10 mode into a Quasi-TEM mode and feeding it into the plane wave transition structure; the plane wave transition structure is used to feed the Quasi-TEM mode into the upper dielectric substrate planar waveguide.

[0016] Preferably, the plane wave transition structure is implemented by a profiled step waveguide, which is composed of a planar waveguide and a raised parabolic profiled waveguide, and a step matching transition structure is provided at the connection between the planar waveguide and the parabolic profiled waveguide, and the lower side cutting angle of the planar waveguide is set to optimize the matching; the planar waveguide is used to guide the Quasi-TEM mode to be transmitted to the parabolic profiled waveguide through the step matching transition structure, and then the Quasi-TEM mode is input to the upper dielectric substrate slab waveguide through the parabolic profiled waveguide.

[0017] Preferably, a plurality of evenly distributed circular groove arrays are provided on the lower surface of the upper metal plate located directly above the dielectric layer and the upper surface of the lower metal plate located directly below the dielectric layer to suppress energy leakage.

[0018] Preferably, the lower metal plate is formed by processing and assembling an upper cover plate and a lower cover plate.

[0019] Preferably, a positioning hole is provided in the outer area of ​​the medium disc, a pin is inserted into the positioning hole, the lower end of the pin is fixedly connected to a driving device located in the lower cover plate, and driven by the driving device, the pin drives the metal disc to rotate left and right; at the same time, a sliding track for the pin to move is provided on the lower metal plate.

[0020] The antenna feeds input signals through two waveguide ports on the lower metal disk. The two waveguide ports correspond to the left-hand circular polarization state and the right-hand circular polarization state of the antenna respectively. When one of the waveguide ports is fed, the other waveguide port exists as a matching port. The input signal fed into the waveguide port enters the planar horn through the step matching waveguide and is converted into the TE10 mode, and then converted into the Quasi-TEM mode through the trapezoidal planar waveguide. Next, the difference from the traditional VICTS antenna is that the present invention does not have a separate flat waveguide layer, but combines the radiation layer and the flat waveguide layer, and replaces it with a double-sided single-layer dielectric plate. The Quasi-TEM mode is fed to the dielectric substrate flat waveguide through the special-shaped step waveguide as a plane wave transition structure, and the electromagnetic wave then travels to the dielectric disk through the dielectric substrate flat waveguide and completes the radiation. The present invention can realize left-hand circular polarization and right-hand circular polarization respectively by switching different feed ports, and the dielectric disk realizes mechanical auxiliary scanning of the beam by rotating.

[0021] The invention provides a dual circular polarization large angle scanning low-cost microstrip antenna working in Ka, which solves the problem that the polarization of the traditional VICTS antenna design is linear polarization, which is greatly affected by multipath interference and is not conducive to satellite communication, and the problem that the beam coverage range of the traditional Pillbox antenna design is limited and the scanning angle is small. Its basic working principle is similar to that of the traditional VICTS antenna, and it can be directly used to replace the existing VICTS antenna without changing the relevant control and servo technology. It has the characteristics of wide beam scanning range, circular polarization, low profile and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the overall structural view of the Ka low-cost dual circularly polarized large-angle scanning microstrip array antenna of the present invention.

[0023] Figure 2 This is an exploded view of the overall structure of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0024] Figure 3 It is a schematic structural diagram of the upper metal plate of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0025] Figure 4 The schematic diagram of the structure of the dielectric layer and its placement position of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0026] Figure 5 It is a schematic diagram of the radiation structure of the Ka low-cost dual circularly polarized large-angle scanning microstrip array antenna of the present invention.

[0027] Figure 6 It is a schematic structural diagram of the cover plate on the lower metal plate of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0028] Figure 7 It is a structural schematic diagram of the lower metal plate lower cover of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0029] Figure 8 This is an exploded view of the local structure of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0030] Fig. 9 This is the right-hand circular polarization scanning result of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0031] Fig.10 This is the left-hand circular polarization scanning result of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of the present invention.

[0032] Explanation of the accompanying drawings: 1100. Upper metal plate, 1200. Circular groove array on the lower surface of the upper metal plate, 1300. Circular through hole, 2100. Left dielectric substrate flat waveguide, 2200. Dielectric disk, 2300. Right dielectric substrate flat waveguide, 2210. Microstrip transmission line, 2220. Trapezoidal transition structure, 2230. Rectangular radiation patch, 2231. U-shaped groove, 2240. Positioning hole, 2400. Upper cover plate on the lower metal plate, 2410. Circular groove array on the upper surface of the cover plate on the lower metal plate, 2420. Sliding track, 3100. Lower cover plate of the lower metal plate, 3110. Step matching waveguide, 3120. Planar horn, 3130. Trapezoidal planar waveguide, 3140. Feed waveguide. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0034] This embodiment provides a dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka, such as Figure 1 and Figure 2 As shown, the antenna is mirror-symmetrical on the left and right, and includes a lower metal plate, a dielectric layer, and an upper metal plate arranged in sequence from bottom to top; wherein the lower metal plate is formed by processing and assembling an upper cover plate and a lower cover plate.

[0035] The lower metal plate is provided with a feeding network, such as Figure 7 , Figure 8As shown, the feeding network is divided into two parts, the left part includes a step-matching waveguide, a planar speaker, a trapezoidal planar waveguide, and a planar wave transition structure, and the right part is mirror-symmetrical to the left part; wherein the step-matching waveguide is vertically arranged, and its input port is a standard waveguide port and is located at the bottom of the lower metal plate, which is used to feed the input signal into the planar speaker; the planar speaker is horizontally arranged in the lower metal plate, which is used to convert the input signal into TE 10 mode and feed it into a trapezoidal planar waveguide; the trapezoidal planar waveguide is laterally arranged in the lower metal plate, and is used to convert the TE10 mode into a Quasi-TEM mode and feed it into a plane wave transition structure; the plane wave transition structure is realized by a special-shaped step waveguide, and the special-shaped step waveguide is composed of a planar waveguide and a raised parabolic special-shaped waveguide, and a step matching transition structure is arranged at the connection between the planar waveguide and the parabolic special-shaped waveguide, and the lower side cutting angle of the planar waveguide is arranged to optimize the matching; the planar waveguide is used to guide and transmit the Quasi-TEM mode to the parabolic special-shaped waveguide through the step matching transition structure, and then input the Quasi-TEM mode into the upper dielectric substrate planar waveguide through the parabolic special-shaped waveguide.

[0036] The dielectric layer, such as Figure 4 As shown, it includes a dielectric disk located in the middle, and two dielectric substrate flat waveguides symmetrically arranged on the left and right sides of the dielectric disk. The dielectric substrate flat waveguide is used to transmit the fed Quasi-TEM mode to the dielectric disk; the dielectric disk is used to realize circular polarization radiation, when the dielectric disk receives the Quasi-TEM mode of the left feeding branch, it realizes right-handed circular polarization, and when the dielectric disk receives the Quasi-TEM mode of the right feeding branch, it realizes left-handed circular polarization. At the same time, the outer area of ​​the dielectric disk is provided with a positioning hole, and a pin is inserted into the positioning hole. The lower end of the pin is fixedly connected to the driving device located in the lower cover plate. Driven by the driving device, the pin drives the metal disk to rotate left and right; at the same time, a sliding track for the pin to move is provided on the lower metal plate. The dielectric disk rotates left and right under external drive, thereby changing the beam direction and realizing mechanical auxiliary scanning.

[0037] Specifically, the dielectric substrate planar waveguide comprises a dielectric substrate and copper clad layers on its upper and lower surfaces. The outer side of the dielectric substrate is arc-shaped, the inner side is semicircular, and a stepped structure is arranged along the electromagnetic wave transmission direction. An arc-shaped groove matching the shape of the output port of the feeding network is etched on the outer edge of the copper clad layer on the lower surface of the dielectric substrate, serving as the input port of the dielectric substrate planar waveguide. The output port of the dielectric substrate planar waveguide is a cylindrical surface close to the dielectric disk.

[0038] Specifically, Figure 5As shown, the dielectric disk includes a circular dielectric substrate and copper-clad layers on its upper and lower surfaces, wherein a radiation structure is arranged in the middle of the copper-clad layer on the upper surface; the radiation structure includes 24 parallel microstrip transmission lines and 192 radiation units; both ends of the microstrip transmission line are arranged as trapezoidal transition structures to optimize matching; the radiation units are arranged in a triangular grid, and each radiation unit is composed of 4 rectangular radiation patches located on both sides of the microstrip transmission line, and a U-shaped groove is arranged in the middle of the radiation patch to reduce the volume of the radiation patch; each rectangular radiation patch has a vertex connected to the microstrip transmission line, and the spacing between the vertex angles along the direction of electromagnetic wave travel is one-quarter of the working wavelength, and the rectangular radiation patches are rotated 90° in sequence to achieve dual circular polarization.

[0039] like Figure 3 As shown, the upper metal plate is used to press and fix the dielectric layer, and a circular through hole is provided in the central region thereof, the radius of the circular through hole is smaller than the radius of the direct disk and larger than the radiation opening surface of the dielectric disk.

[0040] A plurality of evenly distributed circular groove arrays are arranged on the lower surface of the upper metal plate located directly above the dielectric layer and the upper surface of the lower metal plate located directly below the dielectric layer to suppress energy leakage.

[0041] When the antenna of the present invention is working, when the dielectric disk rotates a certain angle, the plane wave traveling through the dielectric substrate planar waveguide enters the dielectric disk and forms an inclination angle with the microstrip radiation structure. At this time, a phase difference is generated between the linear arrays in the radiation structure, thereby realizing beam scanning. The radiation structure introduces additional rotary feeding through a triangular array and coupling between adjacent staggered dual circular polarization units, so that the antenna can maintain a better axial ratio during scanning. At the same time, based on the scanning principle of the VICTS structure and the design, a trapezoidal transition structure is set at both ends of the dielectric substrate planar waveguide with a stepped structure and the microstrip transmission line to optimize matching, which can easily achieve large-angle scanning.

[0042] Fig. 9 : is the right-hand circular polarization scanning result of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of this embodiment, Fig.10 The left-hand circular polarization scanning result of the Ka low-cost dual circular polarization large-angle scanning microstrip array antenna of this embodiment is shown in FIG. It can be seen that the low-cost antenna can achieve a large-angle scanning of ±60° through mechanical auxiliary scanning, and the axial ratio of the dual circular polarization can be maintained below 3dB, indicating that the structural performance is excellent.

Claims

1. A dual circular polarization large angle scanning low cost microstrip antenna operating at Ka, characterized in that: The antenna is mirror-symmetrical from left to right, and includes a lower metal plate, a dielectric layer, and an upper metal plate arranged in sequence from bottom to top; The lower metal plate is provided with a feeding network, including two feeding branches arranged symmetrically on the left and right, and the two feeding branches are used to convert the input signal into a Quasi-TEM mode and feed it to the input ports of the dielectric substrate slab waveguide on the left and right sides respectively; at the same time, the upper surface of the lower metal plate is provided with a groove matching the shape of the dielectric layer, which is used to accommodate and fix the dielectric layer; The dielectric layer includes a dielectric disk located in the middle, and two dielectric substrate planar waveguides symmetrically arranged on the left and right sides of the dielectric disk; wherein the dielectric substrate planar waveguide is used to transmit the fed Quasi-TEM mode to the dielectric disk; the dielectric disk is used to realize circularly polarized radiation, and when the dielectric disk receives the Quasi-TEM mode of the left feeding branch, right-hand circular polarization is realized, and when the dielectric disk receives the Quasi-TEM mode of the right feeding branch, left-hand circular polarization is realized, and at the same time, the dielectric disk can rotate left and right under external drive, thereby changing the beam direction and realizing mechanical auxiliary scanning; The upper metal plate is used for pressing and fixing the dielectric layer, and a circular through hole is arranged in the central region thereof, the radius of which is smaller than the radius of the direct disk and larger than the radiation opening of the dielectric disk.

2. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 1, characterized in that: The dielectric disk comprises a circular dielectric substrate and copper-clad layers on its upper and lower surfaces, wherein a radiation structure is arranged in the middle of the copper-clad layer on the upper surface; the radiation structure comprises a plurality of microstrip transmission lines arranged in parallel, and a plurality of radiation units; the radiation units are arranged in a triangular grid, and each radiation unit is composed of four rectangular radiation patches located on both sides of the microstrip transmission line, each rectangular radiation patch has a vertex connected to the microstrip transmission line, and the spacing between the vertex angles along the direction of electromagnetic wave travel is one-quarter of the working wavelength, and the rectangular radiation patches are rotated 90° in sequence to achieve dual circular polarization.

3. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 2, characterized in that: A U-shaped groove is arranged in the middle of the radiation patch.

4. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 2, characterized in that: Trapezoidal transition structures are arranged at both ends of the microstrip transmission line.

5. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 2, characterized in that: The dielectric substrate planar waveguide comprises a dielectric substrate and copper clad layers on its upper and lower surfaces. The outer side of the dielectric substrate is arc-shaped, the inner side is semicircular, and a stepped structure is arranged along the electromagnetic wave transmission direction. An arc-shaped groove matching the shape of the output port of the feeding network is etched on the outer edge of the copper clad layer on the lower surface of the dielectric substrate as the input port of the dielectric substrate planar waveguide. The output port of the dielectric substrate planar waveguide is a cylindrical surface close to the dielectric disk.

6. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 5, characterized in that: The feeding network is divided into two parts, the left part includes a step-matching waveguide, a planar horn, a trapezoidal planar waveguide, and a plane wave transition structure, and the right part is mirror-symmetrical to the left part; wherein the step-matching waveguide is vertically arranged, and its input port is a standard waveguide port and is located at the bottom of the lower metal plate, and is used to feed the input signal into the planar horn; the planar horn is horizontally arranged in the lower metal plate, and is used to convert the input signal into a TE10 mode and feed it into the trapezoidal planar waveguide; the trapezoidal planar waveguide is horizontally arranged in the lower metal plate, and is used to convert the TE10 mode into a Quasi-TEM mode and feed it into the plane wave transition structure; the plane wave transition structure is used to feed the Quasi-TEM mode into the dielectric substrate planar waveguide above.

7. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 6, characterized in that: The plane wave transition structure is realized by a profiled step waveguide, which is composed of a plane waveguide and a raised parabolic profiled waveguide, and a step matching transition structure is arranged at the connection between the plane waveguide and the parabolic profiled waveguide, and a lower side cutting angle of the plane waveguide is arranged; the plane waveguide is used to guide and transmit the Quasi-TEM mode to the parabolic profiled waveguide through the step matching transition structure, and then input the Quasi-TEM mode to the upper dielectric substrate planar waveguide through the parabolic profiled waveguide.

8. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 6, characterized in that: A plurality of evenly distributed circular groove arrays are arranged on the lower surface of the upper metal plate located directly above the dielectric layer and the upper surface of the lower metal plate located directly below the dielectric layer.

9. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 8, characterized in that: The lower metal plate is formed by processing and assembling an upper cover plate and a lower cover plate.

10. A dual circular polarization large angle scanning low-cost microstrip antenna operating at Ka as claimed in claim 9, characterized in that: The outer area of ​​the medium disc is provided with a positioning hole, a pin is inserted into the positioning hole, the lower end of the pin is fixedly connected to the driving device located in the lower cover plate, and driven by the driving device, the pin drives the metal disc to rotate left and right; at the same time, a sliding track for the pin to move is provided on the lower metal plate.

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