A broadband multimode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes

Abstract

The present invention relates to the technical field of radio frequency antennas, and particularly relates to a broadband multimode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes, which includes a dielectric substrate, a four-arm Archimedean microstrip spiral, two groups of PIN diodes, a metal grounding ring, a metal disc and a feeding network. The four-arm Archimedean microstrip spiral is formed by uniformly winding four spiral lines, and two break openings are respectively arranged on the four spiral lines. The two groups of PIN diodes are used to connect the break openings of the spiral lines. The metal grounding ring and the metal disc are located at the bottom end of the circular dielectric substrate. The feeding network is connected to the spiral line and the metal grounding ring. When the present invention is in use, by switching the on-off state of the PIN diodes and switching different feeding positions, the effective inner and outer radius ranges of the overall spiral antenna are regulated to control the operating frequency ranges of the vortex electromagnetic waves of different OAM modes, thereby broadening the common bandwidth of different OAM modes to better meet the application requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency antennas, and particularly to a broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes. Background Art

[0002] Since the discovery of the vortex electromagnetic wave carrying Orbital Angular Momentum (OAM), due to the theoretical infinity and independent orthogonality of the OAM modes, it has the potential to improve the channel capacity and spectrum utilization rate in wireless communication, attracting extensive attention from researchers. It has broad application prospects in fields such as moving object detection, radar imaging, and medical disease detection. Currently, antennas used in the radio frequency field to generate vortex electromagnetic waves include spiral phase plates modulated by beams and reflecting paraboloids, etc.; as well as directly generated single microstrip patch antennas, array antennas, electromagnetic metasurface antennas, and traveling wave antennas, etc. Different antennas have their own advantages and disadvantages in terms of cost, size, complexity of the feeding network, operating frequency, and whether they can generate multi-mode reconfigurable vortex waves.

[0003] The Archimedean planar spiral antenna can be approximated as a circular traveling wave antenna. Due to its characteristics of easy nesting and frequency independence, it has attracted extensive attention. In recent years, the research on the Archimedean planar spiral antenna has experienced a process of exploration from single-arm, double-arm to multi-arm, and its operating frequency has also expanded from single-frequency points, multi-frequency points to wide frequency bands. However, since the operating bandwidths of different OAM modes are still relatively narrow, this undoubtedly limits the further application of OAM in radar imaging, target detection, etc.

[0004] In view of this, the present application aims to provide a broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes to broaden the common bandwidth of different OAM modes and better meet the application requirements of vortex electromagnetic waves. Summary of the Invention

[0005] To solve the above problems, the present invention provides a broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes, which can broaden the common operating frequency range of different OAM modes while generating broadband multi-OAM vortex electromagnetic waves, and finally generate vortex electromagnetic waves with a wide common bandwidth and multiple OAM modes to better meet the application requirements.

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

[0007] A broadband multimode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes, comprising a circular dielectric substrate, a four-arm Archimedean microstrip spiral, two groups of PIN diodes, a metal grounding ring, a metal disc and a feeding network. The four-arm Archimedean microstrip spiral is formed by four spiral lines uniformly wound on the top of the circular dielectric substrate, and the starting winding positions of the four spiral lines are spaced from the center of the circular dielectric substrate. Two break openings are respectively arranged on the four spiral lines, and the two groups of PIN diodes are respectively arranged at the break opening positions on the four spiral lines to connect the two ends of the break openings of the spiral lines. The circular dielectric substrate, the four-arm Archimedean microstrip spiral, the metal grounding ring and the metal disc are concentrically arranged, and the metal grounding ring and the metal disc are located at the bottom of the circular dielectric substrate. A first connection through hole is arranged on the metal grounding ring, and a second connection through hole is arranged on the metal disc corresponding to the starting positions of the four spiral lines. The circular dielectric substrate is respectively provided with through holes at the positions corresponding to the first connection through hole and the second connection through hole for installing and connecting the feeding network;

[0008] During use, by switching the on-off states of the PIN diodes and switching different feeding positions, the effective inner and outer radius ranges of the overall spiral antenna are regulated to control the operating frequency ranges of vortex electromagnetic waves in different OAM modes, thereby broadening the common bandwidth of different OAM modes.

[0009] Furthermore, it further includes a metal reflector, which is arranged at an interval from the circular dielectric substrate and is connected to the feeding network for providing directional radiation.

[0010] Furthermore, the metal reflector is a conical metal reflector.

[0011] Furthermore, the feeding network is composed of eight coaxial lines. The eight coaxial lines are respectively the coaxial lines, and the axial directions of the coaxial lines are perpendicular to the tangential direction of the circular dielectric substrate. The eight coaxial lines respectively have inner conductors and outer conductors. The inner conductors respectively pass through the first connection through hole, the second connection through hole and the through holes on the circular dielectric substrate to be connected to the spiral lines, and the outer conductors are connected to the metal grounding ring.

[0012] Furthermore, the coaxial line is a 50Ω coaxial line.

[0013] Furthermore, the two break openings of the four spiral lines are located on two concentric rings.

[0014] Furthermore, the conduction directions of the two groups of PIN diodes are arranged from the inner end to the outer end of the four-arm Archimedean microstrip spiral.

[0015] Further, the winding positions of the ends of the four helical lines are evenly distributed in a circular pattern.

[0016] Further, the four-arm Archimedean microstrip spiral, the metal ground ring, and the metal disc are respectively printed on the circular dielectric substrate.

[0017] Further, the first connection through-hole, the second connection through-hole, and the perforation are respectively circular.

[0018] The beneficial effects of the present invention are as follows:

[0019] The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes provided by the present invention includes a circular dielectric substrate, a four-arm Archimedean microstrip spiral, two groups of PIN diodes, a metal ground ring, a metal disc, and a feeding network. When in use, by switching the on-off states of the PIN diodes and switching different feeding positions, the effective inner and outer radius ranges of the overall spiral antenna are adjusted to control the operating frequency ranges of the vortex electromagnetic waves in different OAM modes, thereby broadening the common bandwidth of different OAM modes to better meet the application requirements. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of some embodiments of the present application;

[0021] Figure 2 is a schematic structural diagram of some embodiments of the present application;

[0022] Figure 3 is a schematic structural diagram of some embodiments of the present application

[0023] Figure 4 is the reflection coefficient diagram of the antenna in a test example of the present application;

[0024] Figure 5 is the amplitude and phase distribution diagrams of the antenna in the test example of the present application at 3 GHz and 4.5 GHz.

[0025] Description of the Reference Numerals:

[0026] Circular dielectric substrate 1, four-arm Archimedean microstrip spiral 2, PIN diode 3, metal ground ring 4, first connection through-hole 41, metal disc 5, second connection through-hole 51, feeding network 6, metal reflector 7. Detailed Embodiments

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0029] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] As Figures 1 to 2 shown, the broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna for loading multi-PIN diodes 3 in this embodiment includes a circular dielectric substrate 1, a four-arm Archimedean microstrip spiral 2, two groups of PIN diodes 3, a metal ground ring 4, a metal disk 5, and a feeding network 6. The four-arm Archimedean microstrip spiral 2 is formed by four spiral lines evenly wound on the top of the circular dielectric substrate 1, and the starting winding positions of the four spiral lines are spaced from the center of the circular dielectric substrate 1. Two break openings are respectively provided on the four spiral lines, and the two groups of PIN diodes 3 are respectively arranged at the break opening positions on the four spiral lines to connect the two ends of the break openings of the spiral lines. The circular dielectric substrate 1, the four-arm Archimedean microstrip spiral 2, the metal ground ring 4, and the metal disk 5 are concentrically arranged, and the metal ground ring 4 and the metal disk 5 are located at the bottom of the circular dielectric substrate 1. A first connection through hole 41 is provided on the metal ground ring 4, and a second connection through hole 51 is provided on the metal disk 5 corresponding to the starting positions of the four spiral lines. The circular dielectric substrate 1 is respectively provided with through holes at the positions corresponding to the first connection through hole 41 and the second connection through hole 51 for installing and connecting the feeding network 6;

[0031] In use, by switching the state of the PIN diode 3 and switching different feeding positions, the effective inner and outer radius ranges of the overall spiral antenna are regulated to control the operating frequency ranges of vortex electromagnetic waves of different OAM modes, thereby broadening the common bandwidths of different OAM modes.

[0032] In this embodiment, the starting position of each spiral line is located at a certain distance from the center of the circular dielectric substrate 1, and is disconnected at a selected distance from the center. The two ends of the disconnected spiral line are connected by the PIN diode 3. By switching the state of the PIN diode 3, the inner and outer radii of the antenna can be effectively regulated. While generating multiple OAM modes, the common bandwidths of different OAMs are broadened, which is of great significance for the application of vortex electromagnetic waves in high-resolution imaging.

[0033] Specifically, in this embodiment, the two break openings of the four spiral lines are located on two concentric rings; the conduction directions of the two groups of PIN diodes 3 are set from the inner end to the outer end of the four-arm Archimedean microstrip spiral 2; the end winding positions of the four spiral lines are evenly distributed in a ring shape; the four-arm Archimedean microstrip spiral 2, the metal ground ring 4 and the metal disc 5 are respectively printed on the circular dielectric substrate 1; the first connection through hole 41, the second connection through hole 51 and the through hole are respectively set as circular.

[0034] Specifically, the feeding network 6 is composed of eight coaxial lines. The eight coaxial lines are respectively set as coaxial lines, and the axial directions of the coaxial lines are perpendicular to the tangent direction of the circular dielectric substrate 1. Each of the eight coaxial lines has an inner conductor and an outer conductor. The inner conductors respectively pass through the first connection through hole 41, the second connection through hole 51 and the through hole on the circular dielectric substrate 1 to be connected to the spiral line, and the outer conductors are connected to the metal ground ring 4.

[0035] Among them, the coaxial line is set as a 50Ω coaxial line.

[0036] In this embodiment, the inner conductor of the coaxial line passes through the circular dielectric substrate 1 and the grounded metal ring and is connected to the inner diameter end point of the spiral line, and passes through the circular dielectric substrate 1 and the metal disc 5 and is connected to the starting position end point of the spiral line. The outer conductor is connected to the metal ground ring 4, so as to perform feeding position switching adjustment through two groups of feeding networks 6 at different positions.

[0037] See Figure 3 As shown, on the basis of the above embodiment, a metal reflector 7 is further provided. The metal reflector 7 is arranged at an interval from the circular dielectric substrate 1 and is connected to the feeding network 6 for providing directional radiation.

[0038] Specifically, the metal reflector 7 is set as a conical metal reflector 7.

[0039] In this embodiment, a coaxial cable is passed through the metal reflector 7 and connected to the conical antenna body. While realizing power feeding, the metal reflector 7 is fixed to the circular dielectric substrate 1. By adding the metal reflector 7, directional radiation can be achieved and the gain can be improved.

[0040] The following are specific test examples:

[0041] The main structural parameters of the antenna in this test example are shown in Table 1.

[0042] Among them, the radius of the circular dielectric substrate is rs, the diameter and the pitch of the spiral are both w, the initial radius of the innermost loop of the spiral is ri, the radii at the break points of the spiral are c1 and c2 respectively, the spiral growth rate is a, the width of the metal grounding ring is d, and the radius of the metal disc is r1.

[0043] In addition, as Figure 3 shown, a conical metal reflector can be added at a distance of λ0 / 4 from the circular dielectric substrate, where λ0 is the free space wavelength, which is the ratio of the speed of light to the electromagnetic wave frequency. The thickness h of the conical dielectric substrate is 0.762 mm, the dielectric material is Rogers4350B, and its relative dielectric constant ε r = 3.66.

[0044] Table 1 Main structural parameters of the planar spiral antenna

[0045] rs 100 mm w 2 mm ri 8 mm <![CDATA[c1]]> 22 mm <![CDATA[c2]]> 50 mm a 2.55 mm / rad <![CDATA[w1]]> 12 mm <![CDATA[r1]]> 11 mm d 25 mm

[0046] The OAM mode and bandwidth of the vortex electromagnetic wave generated by the planar spiral antenna in the PIN diode conduction state in this test example. For the four-arm Archimedean spiral antenna, it has the following four feeding phase distributions:

[0047]

[0048] When the conical spiral antenna operates in the fundamental mode, it can generate vortex electromagnetic waves with OAM modes l = 0, 1, 2, and 3. Using CST software for simulation, the antenna reflection coefficient is as Figure 4 shown. It can be seen from Figure 4 that the wave port reflection coefficient of the four-arm spiral antenna is below -10 dB in the range of 2.4 - 6 GHz, that is, the planar spiral antenna has good return loss performance in the broadband range.

[0049] The far-field amplitude and phase distribution results of the vortex electromagnetic wave generated by the antenna at 3 GHz and 4.5 GHz are as Figure 5 shown. Its amplitude and phase distribution conform to the characteristics of the vortex electromagnetic wave, indicating that the antenna can generate broadband multimode vortex electromagnetic waves with good performance.

[0050] The specific PIN diode states, feeding positions, generated OAM modes, and mode bandwidths are shown in Table 2.

[0051] Table 2 OAM modes and mode bandwidths generated under different diode states and feeding positions

[0052]

[0053] As can be seen from Table 2, the common operating frequency range of the four different OAM modes is 2.8 - 4.6 GHz, that is, the common bandwidth reaches 1.8 GHz. This is of great significance for the further application of vortex electromagnetic waves in high-resolution radar imaging.

[0054] In summary, the antenna provided by the present invention can generate multi-OAM mode vortex electromagnetic waves by controlling the phase distribution of the feeding network. The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna with loaded diodes provided by the present invention can effectively regulate the inner and outer radii of the antenna by switching the diode switch states. While generating multi-OAM modes, it broadens the common bandwidth of different OAMs, which is of great significance for the application of vortex electromagnetic waves in high-resolution imaging. Moreover, by adding a circular metal reflector of the same size on the basis of the Archimedean planar spiral antenna, the present invention can achieve directional radiation and effectively improve the antenna gain, which is beneficial to the further application of vortex electromagnetic waves.

[0055] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A broadband multimode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes, characterized in that, It includes a circular dielectric substrate, a four-arm Archimedean microstrip spiral, two groups of PIN diodes, a metal grounding ring, a metal disc, and a feeding network. The four-arm Archimedean microstrip spiral is formed by four spiral lines evenly wound around the top of the circular dielectric substrate, and the starting winding positions of the four spiral lines are spaced from the center of the circular dielectric substrate. Two break openings are respectively provided on the four spiral lines, and the two groups of PIN diodes are respectively arranged at the break opening positions on the four spiral lines to connect the two ends of the break openings of the spiral lines. The circular dielectric substrate, the four-arm Archimedean microstrip spiral, the metal grounding ring, and the metal disc are concentrically arranged, and the metal grounding ring and the metal disc are located at the bottom of the circular dielectric substrate. A first connection through hole is provided on the metal grounding ring, and a second connection through hole is provided on the metal disc corresponding to the starting positions of the four spiral lines. The circular dielectric substrate is respectively provided with through holes at the positions corresponding to the first connection through hole and the second connection through hole for installing and connecting the feeding network; During use, by switching the on-off states of the PIN diodes and switching different feeding positions, the effective inner and outer radius ranges of the overall spiral antenna are regulated to control the working frequency ranges of different OAM mode vortex electromagnetic waves, thereby broadening the common bandwidth of different OAM modes; It further includes a metal reflector, which is spaced from the circular dielectric substrate and connected to the feeding network for providing directional radiation; The feeding network is composed of eight coaxial lines. The eight coaxial lines are respectively set as coaxial lines, and the axial directions of the coaxial lines are perpendicular to the tangent direction of the circular dielectric substrate. Each of the eight coaxial lines has an inner conductor and an outer conductor. The inner conductors respectively pass through the first connection through hole, the second connection through hole, and the through holes on the circular dielectric substrate to be connected to the spiral lines, and the outer conductors are connected to the metal grounding ring.

2. The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes according to claim 1, characterized in that The metal reflector is set as a conical metal reflector.

3. The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes according to claim 1, characterized in that, The coaxial line is set as a 50Ω coaxial line.

4. The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes according to claim 1, characterized in that The two break openings of the four spiral lines are located on two concentric rings.

5. The broadband multimode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes according to claim 1, characterized in that, The conduction directions of the two groups of PIN diodes are arranged from the inner end to the outer end of the four-arm Archimedean microstrip spiral.

6. The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes according to claim 1, wherein The winding positions of the ends of the four spiral lines are evenly distributed in a ring shape.

7. The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes according to claim 1, wherein The four-arm Archimedean microstrip spiral, the metal grounding ring, and the metal disc are respectively printed on the circular dielectric substrate.

8. The broadband multi-mode OAM vortex electromagnetic wave planar spiral antenna loaded with multiple diodes according to claim 1, characterized in that, The first connection through hole, the second connection through hole, and the through holes are respectively set as circular.

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