Low-profile miniaturized antenna with radiation structure shared by linear polarization and circular polarization

Abstract

The invention discloses a low-profile miniaturized antenna with a radiation structure shared by linear polarization and circular polarization, and belongs to the technical field of microwave antennas. The antenna provided by the invention realizes the sharing of radiation structures in a vertical polarization mode and a planar circular polarization mode, the circular polarization mode and the vertical polarization mode are generated by respectively utilizing the radial mode and the axial mode of the antenna, the radiation aperture is not additionally increased, the total volume of the antenna is greatly reduced, and the mutual coupling of the two polarization modes is extremely low; the design method is simple, the designed antenna is clear in physical significance, and the performance is easy to adjust; the antenna is based on magnetic current slot radiation, is not limited by 1 / 4 wavelength from the floor, and has an extremely low profile. The method has a wide application prospect in a full-duplex communication system in various fields such as satellite communication, base station communication and aircraft detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave antennas, and specifically relates to a low-profile miniaturized antenna with a shared radiation structure for linear polarization and circular polarization, which is suitable for in-band full-duplex communication systems in various fields such as satellite communication, base station communication and aircraft detection. Background Art

[0002] Antennas are key components in wireless communication systems, and their performance determines the overall performance of the system. Antennas are categorized by polarization as horizontal, vertical, and circular. Antennas with orthogonal polarizations generally exhibit low coupling, such as horizontally and vertically polarized antennas, left-handed and right-handed circularly polarized antennas, and vertically and planar circularly polarized antennas. Leveraging this orthogonal low coupling can effectively increase the channel capacity and enhance communication quality of wireless communication systems.

[0003] When the electric field vector of the antenna wave is perpendicular to the beam incidence plane, we call this antenna a vertically polarized antenna. Early vertically polarized antennas were mainly implemented using monopole antennas, but the cross-section of monopole antennas is generally 1 / 4 wavelength. Although the cross-section has been significantly reduced by improving to a planar monopole structure, it generally lacks a complete floor, which to some extent limits its use.

[0004] In the 5G / 6G communications era, demands for higher signal transmission rates and latency in communication systems are increasing. Multiple-Input Multiple-Output (MIMO) technology is a key technology for addressing this issue and has been widely used in 4G / 5G communication systems. MIMO communication systems feature multiple antennas in the transmitter or receiver, leveraging multipath to achieve higher communication rates and quality without increasing transmit power or system spectrum. However, this requires low mutual coupling between antennas. However, with the advancement of miniaturization in communication equipment, the space reserved for antennas in communication systems is shrinking, often requiring high isolation between antennas at very close spacing. This presents a challenging problem in the antenna field.

[0005] Furthermore, as one of the core technologies of 5G, in-band full-duplex technology offers advantages such as fully utilizing wireless frequency bands, increasing spectrum flexibility, doubling traversal capacity, and reducing feedback delay and end-to-end latency. Compared to traditional half-duplex systems, full-duplex systems can achieve superior data rates and latency performance. However, the transmit and receive antennas of full-duplex devices are often very close together, and the strong mutual coupling between the antennas severely affects the signal-to-noise ratio of the received signal. While digital signal processing can be used to model, estimate, and eliminate interference signals, this often requires complex algorithms.

[0006] In recent years, with the development of satellite communications, antenna requirements have become more stringent. Satellite downlink signals generally use both vertically polarized and circularly polarized antennas to avoid co-channel interference during transmission, thereby increasing communication capacity. Furthermore, for ground-based communication base stations that utilize ground wave transmission, vertically polarized antennas, due to their perpendicularity to the electric field of the ground plane, are less likely to induce polarization currents in the ground during propagation, resulting in lower transmission attenuation.

[0007] In view of the above technical difficulties and practical needs, there is an urgent need for a design method for a low-profile miniaturized antenna with a shared radiation structure of vertical polarization and circular polarization, which can be used in full-duplex communication systems in various fields such as satellite communication, base station communication and aircraft detection. Summary of the Invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a low-profile miniaturized antenna with a shared radiation structure for linear polarization and circular polarization (vertical polarization and planar circular polarization); the circular polarization mode and the vertical polarization mode are generated by the radial mode and the axial mode of the antenna respectively, and the radiation structure sharing of vertical polarization and planar circular polarization is realized without additionally increasing the radiation aperture, which can effectively achieve a significant reduction in the antenna spacing and at the same time maintain a low level of coupling between antennas; the antenna has the advantages of simple structure, extremely low profile and high polarization purity.

[0009] The technical problem proposed by the present invention is solved as follows:

[0010] A low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization includes a first dielectric substrate 1, a main radiator 2, a parasitic radiator 3, a ground plate 4, a second dielectric substrate 5, a feed network 6, a tuning metal pin 7, and a mode adjustment metal pin 8;

[0011] The first dielectric substrate 1 and the second dielectric substrate 5 are circular. The main radiator 2 and the parasitic radiator 3 are located on the upper surface of the first dielectric substrate 1. The main radiator 2 is circular, with its center coinciding with the center of the first dielectric substrate 1. The 4M parasitic radiators 3 have the same structure and are fan-shaped, evenly distributed around the main radiator 2, with gaps between them, where M is a positive integer ≥ 2. The parasitic radiators 3 and the main radiator 2 have their centers coinciding.

[0012] The first dielectric substrate 1, the ground plate 4, and the second dielectric substrate 5 are tightly fitted from top to bottom. 4N tuning metal pins 7 are provided between the main radiator 2 and the ground plate 4, where N is a positive integer ≥ 2. The tuning metal pins 7 pass through the first dielectric substrate 1, with their ends connected to the main radiator 2 and the ground plate 4, respectively. The tuning metal pins 7 are cocircular, with the center of the cocircle coinciding with the center of the main radiator 2, and are evenly distributed between adjacent rectangular slots 13.

[0013] A mold-adjusting metal pin 8 is provided between each parasitic radiator 3 and the ground plate 4. The mold-adjusting metal pin 8 passes through the first dielectric substrate 1, and its two ends are respectively connected to the parasitic radiator 3 and the ground plate 4;

[0014] The feeding network 6 is located on the lower surface of the second dielectric substrate 5 and includes a 90° phase shift structure and single-branch impedance matching networks cascaded at both ends thereof;

[0015] For the two ports of the 90° phase-shifted structure in the feeding network 6, one port serves as a matching port 11 for connecting to a matching load; the other port serves as a circularly polarized feeding port 9. The inner conductor of the first coaxial feed line passes through the second dielectric substrate 5 and is connected to the ground plane 4, while the outer conductor is connected to the circularly polarized feeding port 9. The ends of the single-branch impedance matching network are connected to the main radiator 2 via metal probes 12. The central angle between the two probes 12 and the adjacent rectangular slots 13 is 45°.

[0016] The outer conductor of the second coaxial feed line is connected to the ground plate 4 , and the inner conductor passes through the first dielectric substrate 1 and is connected to the center position of the main radiator 2 .

[0017] Furthermore, the first dielectric substrate 1 , the main radiator 2 , the parasitic radiator 3 , the ground plate 4 , the tuning metal pin 7 and the mode-adjusting metal pin 8 constitute a vertically polarized antenna, which is fed by the second coaxial feed line.

[0018] Furthermore, the first dielectric substrate 1 , the main radiator 2 , the parasitic radiator 3 , the ground plate 4 , the second dielectric substrate 5 and the feeding network 6 constitute a circularly polarized antenna, which is fed by the first coaxial feed line.

[0019] Furthermore, the main radiator 2 is further provided with four rectangular slots 13 , which are evenly distributed in the radial direction of the main radiator 2 . Two adjacent rectangular slots 13 are perpendicular to each other, and the extension lines of the rectangular slots 13 reach the center of the circle.

[0020] Furthermore, the matching and radiation pattern of the vertical polarization mode can be adjusted by adjusting the number and position of the tuning metal pins 7 .

[0021] Furthermore, the radiation pattern of the parasitic radiator 3 is adjusted by adjusting the position of the mold-adjusting metal pin 8 .

[0022] Furthermore, M=2, N=2.

[0023] The beneficial effects of the present invention are:

[0024] The antenna of the present invention realizes the sharing of vertical polarization mode and planar circular polarization mode radiation structure, greatly reducing the total volume of the antenna, while the mutual coupling between the two polarization modes is extremely low; the design method is simple, the physical meaning of the designed antenna is clear, and the performance is easy to adjust; the antenna is based on magnetic flux gap radiation, is not limited by 1 / 4 wavelength from the floor, and has an extremely low profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the three-dimensional structure of the antenna of the present invention;

[0026] Figure 2 1 is a plan view of the antenna of the present invention, wherein (a) is a top view and (b) is a bottom view;

[0027] Figure 3 is a reflection coefficient curve diagram of the antenna described in the embodiment;

[0028] Figure 4 is an isolation curve diagram of the antenna described in the embodiment;

[0029] Figure 5 is an axial ratio curve of the circularly polarized radiation pattern of the antenna in the 0° direction described in the embodiment;

[0030] Figure 6 The simulated radiation pattern of the antenna described in the embodiment at 7.1 GHz, where (a) is circular polarization and (b) is vertical polarization;

[0031] Figure 7 The E-plane and H-plane radiation patterns of the antenna in the embodiment in circular polarization mode;

[0032] Figure 8 The E-plane and H-plane radiation patterns of the antenna in the embodiment in the online mode;

[0033] Figure 9 1 is the gain diagram of the main lobe direction of the antenna in the embodiment in the circular polarization mode and the vertical polarization mode. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the accompanying drawings and examples.

[0035] This embodiment provides a low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization. The three-dimensional structure diagram is shown in FIG. Figure 1 As shown, the top view is Figure 2 (a) shows the bottom view. Figure 2 As shown in (b), it includes a first dielectric substrate 1, a main radiator 2, a parasitic radiator 3, a ground plate 4, a second dielectric substrate 5, a feeding network 6, a tuning metal pin 7 and a mode adjustment metal pin 8;

[0036] The first dielectric substrate 1 and the second dielectric substrate 5 are circular. The main radiator 2 and the parasitic radiator 3 are located on the upper surface of the first dielectric substrate 1. The main radiator 2 is circular, and its center coincides with the center of the first dielectric substrate 1. The eight parasitic radiators 3 have the same structure and are fan-shaped. They are evenly distributed around the main radiator 2 and have gaps between them. The parasitic radiators 3 coincide with the center of the main radiator 2.

[0037] In this embodiment, the main radiator 2 is further provided with four rectangular slots 13 , which are evenly distributed in the radial direction of the main radiator 2 . Two adjacent rectangular slots 13 are perpendicular to each other, and the extension lines of the rectangular slots 13 reach the center of the circle.

[0038] The first dielectric substrate 1, ground plate 4, and second dielectric substrate 5 are tightly fitted together from top to bottom. Eight tuning metal pins 7 are positioned between the main radiator 2 and ground plate 4. These pins pass through the first dielectric substrate 1, with their ends connected to the main radiator 2 and ground plate 4, respectively. The tuning metal pins 7 are cocircular, with their center coinciding with the center of the main radiator 2, and are evenly distributed between adjacent rectangular slots 13. Adjusting the number and position of the tuning metal pins 7 allows for adjustment of the vertical polarization mode matching and radiation pattern.

[0039] A mode-adjusting metal pin 8 is provided between each parasitic radiator 3 and the ground plate 4. The mode-adjusting metal pin 8 passes through the first dielectric substrate 1, and its two ends are respectively connected to the parasitic radiator 3 and the ground plate 4; the radiation pattern of the parasitic patch can be adjusted by adjusting the position of the mode-adjusting metal pin 8.

[0040] The feeding network 6 is located on the lower surface of the second dielectric substrate 5 and includes a typical 90° phase-shifting structure (branch line coupler) and a single-branch impedance matching network cascaded at both ends. It can also be implemented by combining other phase-shifting networks (circulator, digital phase shifter, microstrip phase shifter) and a general impedance transformation network.

[0041] For the two ports of the 90° phase-shifted structure in the feeding network 6, one port serves as a matching port 11 for connecting to a matching load; the other port serves as a circularly polarized feeding port 9, the inner conductor of the first coaxial feed line passes through the second dielectric substrate 5 and is connected to the ground plate 4, and the outer conductor is connected to the circularly polarized feeding port 9; the ends of the single-branch impedance matching network are respectively connected to the main radiator 2 through metal probes 12; the central angle between the two probes 12 and their adjacent rectangular slots 13 is 45°.

[0042] The outer conductor of the second coaxial feed line is connected to the ground plate 4 , and the inner conductor passes through the first dielectric substrate 1 and is connected to the center position of the main radiator 2 .

[0043] In this embodiment, the first dielectric substrate 1, the main radiator 2, the parasitic radiator 3, the ground plate 4, the tuning metal pin 7 and the mode-adjusting metal pin 8 constitute a vertically polarized antenna, which is fed by a second coaxial feeder. The tuning metal pin 7 is used to adjust the matching of the vertically polarized antenna pattern, and the mode-adjusting metal pin 8 is used to adjust the radiation pattern of the parasitic radiator 3, which radiates vertically polarized waves together with the main radiator 2.

[0044] The first dielectric substrate 1, the main radiator 2, the parasitic radiator 3, the ground plate 4, the second dielectric substrate 5 and the feeding network 6 constitute a circularly polarized antenna, which is fed by a first coaxial feeder. The first coaxial feeder is connected to the circularly polarized feeding port 9 to realize the excitation of the circularly polarized antenna. After passing through the feeding network 6, the metal probe 12 feeds the main radiator 2, thereby exciting mutually orthogonal horizontal polarization modes to synthesize circularly polarized waves.

[0045] The reflection coefficient curve of the antenna in this embodiment is as follows: Figure 3 As shown, the isolation curve is as follows Figure 4 shown. Figure 3 Port 1 is the port corresponding to the second coaxial feeder, and port 2 is the port corresponding to the first coaxial feeder. It can be seen that the vertical polarization mode and the plane circular polarization mode are well excited. Figure 4 It can be seen that the isolation between port 1 and port 2 is good, because the corresponding planar ring magnetic current source and radial magnetic current source are orthogonal to each other, so they naturally have good isolation.

[0046] The axial ratio curve of the circularly polarized radiation pattern of the antenna in this embodiment in the 0° direction is as follows: Figure 5 As shown, it can be seen that the circularly polarized mode radiates well near 7.1 GHz, and the axial ratio is better than 0.52 dB.

[0047] The simulated radiation pattern of the antenna in this embodiment at 7.1 GHz is as follows: Figure 6 As shown in the figure, (a) is circular polarization and (b) is vertical polarization. The simulation is implemented by feeding one port and connecting the other ports to matching loads. The E-plane and H-plane radiation patterns of the antenna in the circular polarization mode of this embodiment are shown in the figure. Figure 7 As shown, the E-plane and H-plane directional patterns in the online mode are as follows Figure 8 As shown in the figure, it can be seen that the polarization purity of the circular polarization mode and the vertical polarization mode in their respective main lobe directions is very high. Due to the orthogonality of the radiation currents of the vertical polarization mode and the circular polarization radiation mode, their radiation patterns also show good complementarity.

[0048] The gain diagrams of the antenna in the embodiment in the main lobe direction in the circular polarization mode and the vertical polarization mode are as follows: Figure 9 As shown, it can be seen that both the vertical polarization mode and the circular polarization radiation mode have good gains.

Claims

1. A low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization, characterized in that: It comprises a first dielectric substrate (1), a main radiator (2), a parasitic radiator (3), a grounding plate (4), a second dielectric substrate (5), a feeding network (6), a tuning metal pin (7) and a mode adjustment metal pin (8); The first dielectric substrate (1) and the second dielectric substrate (5) are circular; the main radiator (2) and the parasitic radiator (3) are located on the upper surface of the first dielectric substrate (1); the main radiator (2) is circular, and the center thereof coincides with the center thereof of the first dielectric substrate (1); the 4M parasitic radiators (3) have the same structure, are fan-shaped, and are evenly distributed around the main radiator (2), with gaps between them and the main radiator (2), where M is a positive integer ≥ 2; the centers of the parasitic radiators (3) and the main radiator (2) coincide; The first dielectric substrate (1), the grounding plate (4), and the second dielectric substrate (5) are tightly fitted from top to bottom; 4N tuning metal pins (7) are provided between the main radiator (2) and the grounding plate (4), where N is a positive integer ≥ 2; the tuning metal pins (7) pass through the first dielectric substrate (1), and the two ends are respectively connected to the main radiator (2) and the grounding plate (4); the tuning metal pins (7) are cocircular, and the center of the cocircle coincides with the center of the main radiator (2); A mold adjustment metal pin (8) is provided between each parasitic radiator (3) and the grounding plate (4); the mold adjustment metal pin (8) passes through the first dielectric substrate (1), and its two ends are respectively connected to the parasitic radiator (3) and the grounding plate (4); The feeding network (6) is located on the lower surface of the second dielectric substrate (5), and includes a 90° phase shift structure and single-branch impedance matching networks cascaded at both ends thereof; For the two ports of the 90° phase-shifted structure in the feeding network (6), one port is used as a matching port (11) for connecting to a matching load; the other port is used as a circularly polarized feeding port (9); the inner conductor of the first coaxial feed line passes through the second dielectric substrate (5) and is connected to the ground plate (4), and the outer conductor is connected to the circularly polarized feeding port (9); the ends of the single-branch impedance matching network are connected to the main radiator (2) through metal probes (12); the central angle between the two probes (12) and the adjacent rectangular slots (13) is 45°; The outer conductor of the second coaxial feed line is connected to the ground plate (4), and the inner conductor passes through the first dielectric substrate (1) and is connected to the center position of the main radiator (2).

2. The low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization according to claim 1, characterized in that: The first dielectric substrate (1), the main radiator (2), the parasitic radiator (3), the ground plate (4), the tuning metal pin (7) and the mode-adjusting metal pin (8) constitute a vertically polarized antenna, which is fed by a second coaxial feed line.

3. The low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization according to claim 1, characterized in that: The first dielectric substrate (1), the main radiator (2), the parasitic radiator (3), the ground plate (4), the second dielectric substrate (5) and the feeding network (6) constitute a circularly polarized antenna, and the feeding is achieved by the first coaxial feed line.

4. The low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization according to claim 1, characterized in that: The main radiator (2) is further provided with four rectangular slots (13) which are evenly distributed in the radial direction of the main radiator (2), two adjacent rectangular slots (13) are perpendicular to each other, and the extension lines of the rectangular slots (13) reach the center of the circle.

5. The low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization according to claim 1, characterized in that: The matching and radiation pattern of the vertical polarization mode are adjusted by adjusting the number and position of the tuning metal pins (7).

6. The low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization according to claim 1, characterized in that: The radiation pattern of the parasitic radiator (3) is adjusted by adjusting the position of the mold-adjusting metal pin (8).

7. The low-profile miniaturized antenna with a common radiation structure for linear polarization and circular polarization according to claim 1, characterized in that: M=2, N=2.

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