Dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna

Abstract

The invention discloses a dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna, which comprises a dual-linear-polarization mode and a dual-circular-polarization mode, and realizes the selection of the dual-linear-polarization mode and the dual-circular-polarization mode by controlling the feed amplitude and phase difference of multiple ports. Quasi-TEM waves are generated through the metal stepped horn antenna and the planar multi-layer feed structure, multiple modes of independent dual-linear polarization and dual right-handed / left-handed circular polarization are realized by adopting a cross-shaped slot structure and a multi-layer substrate integrated waveguide (SIW) feed line, and the size of the antenna can be effectively reduced. The linear polarization working mode and the circular polarization working mode of the TEM antenna both have broadband return loss (less than-10dB) and high gain of 8.2-10.9 dBi in the working range of 18-19.5 GHz, and when the TEM antenna works as a circular polarization antenna, the axial ratio (AR) of the antenna is less than 3dB in the frequency range.

Description

Technical Field

[0001] The present invention belongs to the technical field of antenna design, and particularly relates to a miniaturized broadband TEM antenna with dual linear polarization, dual circular polarization and multi-mode characteristics. Background Art

[0002] With the development of modern wireless communication systems, in addition to the increasing requirements for the performance characteristics of antennas such as frequency band performance, size, and gain, antennas are also required to have multi-mode and multi-functional characteristics. Antennas with selectable multi-polarization modes can enhance the flexibility and multi-scenario functions of communication systems.

[0003] Due to the advantages of its horn structure, TEM antennas can provide superior performance such as high gain, wide frequency band, simple structure, low dispersion, low distortion, and high power handling capacity, and are applied in fields such as ultra-wideband systems, high-power microwaves (HPM), electromagnetic compatibility (EMC) measurements, and ground penetrating radar.

[0004] However, due to the large size of traditional TEM antennas, their usage scenarios are greatly restricted. Therefore, in recent years, the miniaturization of TEM antennas has received increasing attention. The size of TEM antennas can be reduced while maintaining a wide frequency band through a ridged waveguide structure or a stepped horn structure.

[0005] Due to the need for more polarization modes and miniaturization, several designs of dual-linear polarization TEM antennas (1. J. A. Cazden, M. A. Elmansouri and D. S. Filipovic, "Wideband Miniaturized Dual-Polarized TEM Horn," 2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, Montreal, QC, Canada, 2020, pp. 483-484, doi: 10.1109 / IEEECONF35879.2020.9330305.) and circular polarization TEM antenna arrays (2. G. Strauss and K. Breitsameter, "A circular polarized tem horn antenna array with large scanning angle," 2011 IEEE Radio and Wireless Symposium, Phoenix, AZ, USA, 2011, pp. 98-101, doi: 10.1109 / RWS.2011.5725477. 3. M. A. Elmansouri, J. Ha and D. S. Filipovic, "Ultrawideband TEM Horn Circular Array," in IEEE Transactions on Antennas and Propagation, vol. 65, no. 3, pp. 1374-1379, March 2017, doi: 10.1109 / TAP.2016.2637871.) have been successively published. The design principle of the dual-linear polarization TEM antenna is to form orthogonal dual-linear polarization waves through mutually perpendicular horn structures, while the circular polarization TEM antenna is achieved through a circular polarization TEM array.

[0006] However, existing antennas can only achieve a certain polarization mode, with low flexibility and it is difficult to adapt to the rapidly developing modern communication devices. Therefore, researching a multi-mode antenna will have strong market competitiveness and development prospects. Summary of the Invention

[0007] The object of the present invention is to provide a miniaturized broadband TEM antenna with dual linear polarization and dual circular polarization multi - modes in view of the problems existing in the above - mentioned prior art. The antenna introduces a cross - shaped slot structure, combines a multi - layer planar SIW feeder and mutually perpendicular metal horn structures, and can generate mutually perpendicular dual - linear - polarization TEM waves. By combining the mutually perpendicular dual - linear - polarization TEM waves with a ±90 - degree phase difference, dual left - hand / right - hand circularly polarized waves are realized.

[0008] The technical solution for achieving the object of the present invention is: a miniaturized broadband TEM antenna with dual linear polarization and dual circular polarization multi - modes, the antenna includes a dual - linear - polarization mode and a dual - circular - polarization mode, and realizes the switching selection of modes through multi - port control; specifically: the antenna realizes the selection of the dual - linear - polarization mode and the dual - circular - polarization mode by controlling the feeding amplitude and phase difference of the multi - ports.

[0009] Further, the multi - ports include two mutually perpendicular ports 1 and 2;

[0010] When realizing the dual - linear - polarization mode: port 1 is fed alone, and the TEM antenna realizes the linear - polarization mode radiation with the electric - field direction along the first direction; port 2 is fed alone, and the TEM antenna realizes the linear - polarization mode radiation with the electric - field direction along the second direction; the first direction and the second direction are mutually perpendicular;

[0011] When realizing the dual - circular - polarization mode: when port 1 and port 2 are fed simultaneously and port 1 leads port 2 by 90 degrees in phase, the TEM antenna realizes the right - hand circular - polarization mode radiation; when port 1 and port 2 are fed simultaneously and port 2 leads port 1 by 90 degrees in phase, the TEM antenna realizes the left - hand circular - polarization mode radiation.

[0012] Further, the antenna includes a metal horn part and an SIW feeding part. The SIW feeding part includes an upper - layer SIW feeding structure and a lower - layer SIW feeding structure arranged in sequence from top to bottom. A first SIW port is arranged in the upper - layer SIW feeding structure as port 1, and a second SIW port is arranged in the lower - layer SIW feeding structure as port 2. A cross - shaped slot structure is provided on the metal layer at the connection between the metal horn part and the upper - layer SIW feeding structure, and the two sides of the "cross" are respectively along the first direction and the second direction, and are respectively used for feeding port 2 and feeding port 1; an L - shaped rectangular slot structure is provided on the metal layer at the connection between the upper - layer SIW feeding structure and the lower - layer SIW feeding structure, and the L - shaped rectangular slot structure is arranged along the first direction and is directly below the slot along the first direction in the cross - shaped slot structure.

[0013] Further, the lengths of the cross - shaped slot structure and the L - shaped rectangular slot structure do not exceed the range of the metal horn part.

[0014] Further, the structural parameters of the slots in the cross-shaped slot structure along the first direction are the same as those of the linear rectangular slot.

[0015] Further, the upper-layer SIW feeding structure includes a first metal layer, a first dielectric layer, and a second metal layer arranged in sequence from top to bottom, and the lower-layer SIW feeding structure includes a second metal layer, a second dielectric layer, and a third metal layer arranged in sequence from top to bottom; the cross-shaped slot structure is arranged on the first metal layer, and the linear rectangular slot structure is arranged on the second metal layer.

[0016] Further, the metal horn is of a stepped structure.

[0017] Further, the metal horn includes four stepped rectangular metal blocks, each of which is of a structure with a narrower upper part and a wider lower part; the four stepped rectangular metal blocks are respectively located in the four quadrants formed by the cross-shaped slot structure and are connected at the bottom, and two of the stepped rectangular metal blocks form a horn structure.

[0018] Further, the four stepped rectangular metal blocks are symmetrically arranged about the center of the cross-shaped slot structure.

[0019] Further, both SIW ports are matched with the externally connected 50Ω coaxial line structure through the conversion structures of each layer of SIW and microstrip.

[0020] Compared with the prior art, the significant advantages of the present invention are as follows:

[0021] (1) For the first time, a multi-mode TEM antenna is innovatively proposed. By controlling two ports through a digital system, it can generate selectable dual linear polarization / dual circular polarization waves (by introducing a cross-shaped slot structure, combining a multi-layer planar SIW feeder, and mutually perpendicular metal horn structures, this antenna can generate mutually perpendicular dual linear polarization TEM waves; by combining the mutually perpendicular dual linear polarization TEM waves with a ±90-degree phase difference, dual left-handed / right-handed circular polarization waves are realized), and it has extremely low delay, which is very suitable for application in modern communication systems with multiple functions and multiple scenarios.

[0022] (2) When realizing the dual linear polarization mode, single feeding of port 1 or port 2 will excite linear polarization radiation. Due to the vertical structure at the port feeding connection, the stepped rectangular metal horn structure divided into four parts, and the cross-shaped slot structure at the gap of the metal horn structure all have the characteristics of a vertical multi-mode structure along the X-axis direction and the Y-axis direction, there is a high isolation degree between the two ports, and mutual influence between the two ports will be avoided when realizing the linear polarization mode.

[0023] (3) The combination of the cross-shaped slot structure and the SIW planar multi-layer feeding structure, supplemented by the design of the stepped metal horn structure, significantly reduces the mutual interference and influence between ports and different modes, and also realizes a significant reduction in the size and height of the antenna, effectively achieving miniaturization and low-profile characteristics.

[0024] (4) The present invention has the characteristics of small size, low profile, simple structure, low manufacturing cost, etc., and can provide high antenna gain and wideband performance, and is applicable to large-scale TEM antenna arrays in modern communication systems.

[0025] (5) The linear polarization operating mode and circular polarization operating mode of this TEM antenna both have broadband return loss (less than -10 dB) and high gain of 8.2 - 10.9 dBi in the operating range of 18 - 19.5 GHz. When operating as a circular polarization antenna, the antenna axial ratio (AR) is less than 3 dB within this frequency range.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings. Description of the Drawings

[0027] Figure 1 It is a top view of the miniaturized broadband TEM antenna structure with dual linear polarization and dual circular polarization and multi-mode in one embodiment.

[0028] Figure 2 It is a front view of the miniaturized broadband TEM antenna structure with dual linear polarization and dual circular polarization and multi-mode in one embodiment.

[0029] Figure 3 It is a schematic diagram of the current and electric field directions of the SIW feeding layer during port feeding in one embodiment, where Figure 3 (a) and (b) in it are respectively the current and electric field directions of the SIW feeding layer when feeding at port 1 or port 2.

[0030] Figure 4 It is a schematic diagram of the electric field direction and magnetic field direction of the TEM antenna when feeding at port 1 in one embodiment, where Figure 4 (a) and (b) in it are respectively the schematic diagrams of the electric field direction and magnetic field direction.

[0031] Figure 5 It is a schematic diagram of the electric field direction and magnetic field direction of the TEM antenna when feeding at port 2 in one embodiment, where Figure 5 (a) and (b) in it are respectively the schematic diagrams of the electric field direction and magnetic field direction.

[0032] Figure 6 It is a schematic diagram of the S parameters of the TEM antenna in the linear polarization mode in one embodiment, where Figure 6In (a) and (b), the S-parameters of the TEM antenna are shown when Port 1 and Port 2 are fed separately.

[0033] Figure 7 Fig. (a) and (b) are exemplary diagrams of the far-field radiation pattern of the TEM antenna in the linear polarization mode at 19 GHz when Port 1 is fed, where Figure 7 in (a) and (b), the far-field radiation patterns of the YOZ plane (E-plane) and XOZ plane (H-plane) in the linear polarization mode at 19 GHz are shown respectively.

[0034] Figure 8 Fig. (a) and (b) are exemplary diagrams of the far-field radiation pattern of the TEM antenna in the linear polarization mode at 19 GHz when Port 2 is fed, where Figure 8 in (a) and (b), the far-field radiation patterns of the XOZ plane (E-plane) and YOZ plane (H-plane) in the linear polarization mode at 19 GHz are shown respectively.

[0035] Figure 9 Fig. (a) and (b) are exemplary diagrams of the far-field radiation pattern of the TEM antenna in the circular polarization mode at 19 GHz when Port 1 and Port 2 are fed simultaneously with a 90-degree phase difference, where Figure 9 in (a) and (b), the far-field radiation patterns of the YOZ plane and XOZ plane in the circular polarization mode at 19 GHz are shown respectively.

[0036] Figure 10 Fig. shows an exemplary diagram of the simulated and measured antenna gains of the TEM antenna in the linear polarization mode in the frequency range of 18 GHz to 19.5 GHz in one embodiment.

[0037] Figure 11 Fig. shows an exemplary diagram of the simulated and measured antenna gains of the TEM antenna in the circular polarization mode in the frequency range of 18 GHz to 19.5 GHz in one embodiment.

[0038] Figure 12 Fig. shows an exemplary diagram of the simulated and measured axial ratio (AR) of the circular polarization of the TEM antenna in the frequency range of 18 GHz to 19.5 GHz in one embodiment. Detailed implementation manners

[0039] In order to make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, then such directional indications are only used to explain the relative positional relationship, movement conditions, etc. between components in a certain specific posture (as shown in the drawings). If this specific posture changes, then the directional indications will also change accordingly.

[0041] In addition, if there are descriptions such as "first", "second", etc. involved in the embodiments of the present invention, then such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions results in contradictions or cannot be achieved, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] In one embodiment, a miniaturized broadband TEM antenna with dual linear polarization and dual circular polarization multi - modes is provided. The antenna includes a dual linear polarization mode and a dual circular polarization mode, and realizes the switching selection of modes through multi - port control; specifically: the antenna realizes the selection of the dual linear polarization mode and the dual circular polarization mode by controlling the feeding amplitude and phase difference of the multi - port.

[0043] Further, in one of the embodiments, the multi - port includes two mutually perpendicular ports 1 and 2;

[0044] When realizing the dual linear polarization mode: port 1 is fed alone, and the TEM antenna realizes the linear polarization mode radiation with the electric field direction along the first direction; port 2 is fed alone, and the TEM antenna realizes the linear polarization mode radiation with the electric field direction along the second direction; the first direction and the second direction are mutually perpendicular;

[0045] When realizing the dual circular polarization mode: when port 1 and port 2 are fed simultaneously and port 1 leads port 2 by a phase difference of 90 degrees, the TEM antenna realizes the right - hand circular polarization mode radiation; when port 1 and port 2 are fed simultaneously and port 2 leads port 1 by a phase difference of 90 degrees, the TEM antenna realizes the left - hand circular polarization mode radiation.

[0046] Further, in one of the embodiments, in combination Figure 1, the antenna includes a metal horn part and an SIW feeding part. The SIW feeding part includes an upper-layer SIW feeding structure and a lower-layer SIW feeding structure arranged in sequence from top to bottom. A first SIW port is arranged in the upper-layer SIW feeding structure as the port 1, and a second SIW port is arranged in the lower-layer SIW feeding structure as the port 2. A cross-shaped slot structure is provided on the metal layer at the connection between the metal horn part and the upper-layer SIW feeding structure, and the two sides of the "cross" shape are respectively along the first direction and the second direction, and are respectively used for feeding the port 2 and feeding the port 1; A linear rectangular slot structure is provided on the metal layer at the connection between the upper-layer SIW feeding structure and the lower-layer SIW feeding structure. The linear rectangular slot structure is arranged along the first direction and is directly below the slot along the first direction in the cross-shaped slot structure.

[0047] Preferably here, with the top view of the antenna as the reference, a coordinate system is established, with the horizontal direction as the x-axis and the vertical direction as the y-axis. The x-axis is the second direction and the y-axis is the first direction.

[0048] When the port 1 of the top-layer feeding structure, that is, the upper-layer SIW feeding structure, is fed, the current has little influence on the narrow side of the slot along the Y-axis, but has a greater influence on the wide side along the X-axis. Therefore, the generated radiation electric field is mainly along the Y-axis direction. Due to the orthogonal cross shape of the slot structure, the mutual influence between the feeds of each layer is small and the isolation degree is high. When the port 2 of the bottom-layer feeding structure, that is, the lower-layer SIW feeding structure, is fed, the current has little influence on the narrow side of the slot along the X-axis, but has a greater influence on the wide side along the Y-axis. Therefore, the generated radiation electric field is mainly along the X-axis direction at this time.

[0049] Combined with Figures 2 to 5 , the TEM antenna design of the present invention excites a quasi-TEM wave, whose electric field direction and magnetic field direction are perpendicular to each other, and are located in the XOY plane. The propagation direction is along the Z-axis and is perpendicular to both the electric field direction and the magnetic field direction. The cross-shaped slot structure ensures a high isolation degree between the two input ports, enables two orthogonal linear polarization operations to occur independently, and helps to generate selectable left-handed or right-handed circular polarization waves through two orthogonal linear polarization waves (phase difference of ±90 degrees).

[0050] Preferably, in some embodiments, the lengths of the cross-shaped slot structure and the linear rectangular slot structure do not exceed the range of the metal horn part.

[0051] Preferably, in some embodiments, the structural parameters of the slot along the first direction in the cross-shaped slot structure are the same as those of the linear rectangular slot. Here, the structural parameters include length, width, etc.

[0052] Preferably, in some embodiments, the upper SIW feeding structure includes a first metal layer, a first dielectric layer, and a second metal layer arranged in sequence from top to bottom, and the lower SIW feeding structure includes a second metal layer, a second dielectric layer, and a third metal layer arranged in sequence from top to bottom, and a waveguide structure composed of metal vias on the side; the cross-shaped slot structure is arranged on the first metal layer, and the linear rectangular slot structure is arranged on the second metal layer.

[0053] Preferably, in some embodiments, the metal horn is a stepped structure.

[0054] Here, further preferably, the metal horn portion includes four stepped rectangular metal blocks, each of which is a structure with a narrower upper part and a wider lower part; the four stepped rectangular metal blocks are respectively located in the four quadrants formed by the cross-shaped slot structure and are connected at the bottom, and two of the stepped rectangular metal blocks form a horn structure.

[0055] Here, further preferably, the four stepped rectangular metal blocks are symmetrically arranged about the center of the cross-shaped slot structure.

[0056] Further, in one embodiment, both SIW ports are matched with an externally connected 50Ω coaxial line structure through the conversion structure of each layer of SIW and microstrip.

[0057] It should be noted that the structure is not limited to that in the above embodiments, and other structures with the same implementation principle as the present invention also fall within the protection scope of the present invention.

[0058] As a specific example, in one embodiment, the present invention is further verified and described in detail.

[0059] In this example, the TEM antenna of the present invention is designed in detail. The size of the TEM antenna is designed to be 8 mm × 10 mm (about 0.5λ × 0.6λ), and the antenna height is 6.9 mm (about 0.4λ), where λ is the wavelength at the central operating frequency.

[0060] The material of the stepped metal part of the antenna of the present invention is copper. The two layers of the multi-layer feeding structure are both composed of PCB boards of RO4003C material. The thickness Hd of the dielectric layer is 1.524 mm, the dielectric constant is 3.55, and the loss factor is 0.0027. Combining Figure 1 and Figure 2 , the specific design of each dimension parameter is: the overall length A of the metal horn structure 1 = 8 mm, the overall width A of the metal horn structure 2 = 10 mm, the length L of the rectangular slot of the cross slot structure along the X direction 1 = 10 mm, the width W of the rectangular slot of the cross slot structure along the X direction1 = 0.48 mm, the length L of the rectangular slot of the cross-slot structure along the Y direction 2 = 6.35 mm, the width W of the rectangular slot of the cross-slot structure along the Y direction 2 = 0.95 mm, the width W of the SIW waveguide structure SIW = 11.5 mm, the length L of the top rectangular metal block of the stepped metal horn structure a1 = 2.45 mm, the width W of the top rectangular metal block of the stepped metal horn structure a1 = 4.03 mm, the length L of the bottom rectangular metal block of the stepped metal horn structure a2 = 3.05 mm, the width W of the bottom rectangular metal block of the stepped metal horn structure a2 = 4.38 mm, the height H of the top rectangular metal block of the stepped metal horn structure 1 = 1.6 mm, the height H of the bottom rectangular metal block of the stepped metal horn structure 2 = 1.6 mm, the thickness H of the PCB metal layer c = 0.035 mm, the thickness H of the PCB dielectric layer d = 1.524 mm.

[0061] Through simulation and testing verification, combined with Figure 6 it can be seen that within the designed frequency band of 17.5 GHz to 20 GHz for this TEM antenna, when feeding at port 1 or port 2, a broadband return loss less than -10 dB can be provided. Taking port 2 as an example, considering the phase shift of different layer feeders, a 90-degree phase shift difference with port 1 is achieved by adding a 9-mm SIW feeder at port 2, thus generating a right-handed circularly polarized wave.

[0062] Figures 7 to 9 Shows the linear polarization simulation and test far-field patterns of this TEM antenna when feeding at port 1 or port 2 at the 19-GHz frequency point and the right-handed circular polarization simulation and test far-field patterns obtained by controlling a 90-degree phase difference when feeding at port 1 and port 2 simultaneously, which can show the linear polarization wave and circular polarization wave radiation excited by this TEM antenna in different modes.

[0063] Combined with Figure 10 , it can be seen that within the frequency range of 18 GHz to 19.5 GHz (8%) in the design, when feeding port 1 alone, the linear polarization mode simulation and measured antenna gain range of the TEM antenna is 8.5 to 10.9 dBi, and when feeding port 2 alone, the linear polarization mode simulation and test antenna gain range of the TEM antenna is 8.2 to 10.1 dBi.

[0064] Combined with Figure 11, it can be seen that the simulated and measured antenna gain of the TEM antenna circular polarization mode in the range of 18 GHz to 19.5 GHz (8%) is in the range of 8.4 dBi to 9.8 dBi; combined with Figure 12 , it can be seen that the simulated and measured results of the axial ratio (AR) in this frequency range are both less than 3 dB.

[0065] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and the description in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna, characterized in that: The antenna includes a dual linear polarization mode and a dual circular polarization mode, and realizes mode switching selection through multi-port control; specifically: the antenna realizes the selection of the dual linear polarization mode and the dual circular polarization mode by controlling the feeding amplitude and phase difference of the multi-port.

2. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 1, characterized in that: The multi-port includes two mutually perpendicular ports 1 and 2; When the dual linear polarization mode is implemented: the port 1 is fed alone, and the TEM antenna implements linear polarization mode radiation with the electric field direction along the first direction; The port 2 is fed separately, and the TEM antenna realizes linear polarization mode radiation with the electric field direction along the second direction; the first direction and the second direction are perpendicular to each other; When the dual circular polarization mode is realized: when port 1 and port 2 are fed simultaneously and port 1 leads port 2 with a phase difference of 90 degrees, the TEM antenna realizes right-hand circular polarization mode radiation; when port 1 and port 2 are fed simultaneously and port 2 leads port 1 with a phase difference of 90 degrees, the TEM antenna realizes left-hand circular polarization mode radiation.

3. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 2, characterized in that: The antenna includes a metal horn part and a SIW feeding part, the SIW feeding part includes an upper SIW feeding structure and a lower SIW feeding structure arranged in sequence from top to bottom, a first SIW port is arranged in the upper SIW feeding structure as the port 1, a second SIW port is arranged in the lower SIW feeding structure as the port 2, a cross-shaped slot structure is arranged on the metal layer at the connection between the metal horn part and the upper SIW feeding structure, and two sides of the "cross" are respectively along the first direction and the second direction, and are respectively used for feeding port 2 and feeding port 1; a straight-line rectangular slot structure is arranged on the metal layer at the connection between the upper SIW feeding structure and the lower SIW feeding structure, the straight-line rectangular slot structure is arranged along the first direction, and is located directly below the slot along the first direction in the cross-shaped slot structure.

4. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 3, characterized in that: The lengths of the cross-shaped slot structure and the straight rectangular slot structure do not exceed the range of the metal horn portion.

5. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 3, characterized in that: The structural parameters of the slots along the first direction in the cross-shaped slot structure are the same as the structural parameters of the straight rectangular slots.

6. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 3, characterized in that: The upper SIW feeding structure includes a first metal layer, a first dielectric layer, and a second metal layer arranged in sequence from top to bottom, and the lower SIW feeding structure includes the second metal layer, a second dielectric layer, and a third metal layer arranged in sequence from top to bottom; the cross-shaped slot structure is arranged on the first metal layer, and the straight rectangular slot structure is arranged on the second metal layer.

7. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 3, characterized in that: The metal speaker part is a stepped structure.

8. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 7, characterized in that: The metal horn part includes four stepped rectangular metal blocks, each of which is narrow at the top and wide at the bottom; the four stepped rectangular metal blocks are respectively located in the four quadrants formed by the cross-shaped gap structure and are connected at the bottom, and two of the stepped rectangular metal blocks form a horn structure.

9. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 8, characterized in that: The four stepped rectangular metal blocks are symmetrically arranged about the center of the cross-shaped gap structure.

10. The dual-linear-polarization dual-circular-polarization multi-mode miniaturized broadband TEM antenna according to claim 3, characterized in that: Both SIW ports are matched with the externally connected 50Ω coaxial line structure through the conversion structure of each layer of SIW and microstrip.

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