A broadband dual-ridge waveguide TE21 mode coupler

Abstract

This invention discloses a broadband dual-ridge waveguide TE21-mode coupler, belonging to the field of antenna technology. In this invention, TE... 21 The sub-waveguide of the mode coupler adopts a double-ridge loading configuration. The single-mode operating bandwidth of the double-ridge waveguide is much larger than that of a conventional rectangular waveguide. Therefore, the double-ridge waveguide is used as the TE... 21 The sub-waveguide configuration of the mode coupler can broaden its coupling bandwidth. Simultaneously, the coupling aperture distribution of the coupler, through matching optimization calculations with the double-ridged loaded waveguide, significantly improves the differential-mode coupling and enhances the suppression of the main mode by the sub-waveguide channel. This microwave network possesses numerous advantages, including wide differential-mode coupling bandwidth, high sum-difference isolation, low insertion loss in the sum channel, low VSWR, large power capacity, and strong scalability.

Description

Technical Field

[0001] This invention relates to a wideband TE antenna in the field of antenna technology. 21 The design of the mode coupler achieves a differential-mode operating bandwidth of 1.8:1, making it suitable for broadband signal reception and tracking. Background Technology

[0002] Differential mode tracking is a self-tracking technique that uses higher-order modes with differential mode characteristics in a waveguide to form a differential pattern. TE 11 The mode is the dominant mode in a circular waveguide, generally used as the sum mode, TM. 01 Model and TE 21 Its electric field is weakest in the central region, making it suitable for use as a differential mode. After years of technological development, TE... 21 The self-tracking feed system has become a complete and mature product. In 1982, YOUN H. CHOUNG published a paper on Ku-band TE... 21 The article on mode couplers indicates that differential mode tracking technology has entered engineering applications.

[0003] Cai Chaoguo and others from Chengdu Guowei Communication Technology Co., Ltd. submitted a paper entitled "A TE..." in 2015. 21 The utility model patent for "Mode Coupler Synthesis Network" uses a cylindrical bridge power divider network, avoiding the difficulties of direct winding. However, it only changes the structural installation method and does not effectively improve TE. 21 Performance and operating bandwidth of the mode coupler.

[0004] Hou Yanru and others from Anhui Sifang Electronics Co., Ltd. proposed a method for creating an S-band sixteen-hole TE circuit in 2020. 21 The invention patent for "Mode Coupler" requires only 16 coupling holes per rectangular subwaveguide to achieve current TE coupling. 21 Complete coupling of the modules, while also enabling TE 11 The invention provides suppression of the first and second modes by more than 40 dB and has a more compact structure. It reduces the number of coupling holes and improves the compactness of the coupler without extending its bandwidth.

[0005] Lu Shaopeng and others from the Xi'an Space Radio Technology Research Institute submitted a paper titled "A V-band TE" in 2015. 21 The invention patent for "Mode Tracking Feed", TE 21 The differential-mode coupler adopts asymmetric arm coupling, changing the traditional eight-arm symmetric coupling structure to a four-arm asymmetric coupling structure. The structure is simplified, reducing the difficulty of processing and manufacturing, and it is suitable for applications in the millimeter-wave band and above. Its advantage is also its compact structure, but the improvement in bandwidth is not mentioned.

[0006] In 2014, Qiao Feng of Yantai University designed a Ka-band ultra-wideband tracker. Both the main waveguide and the sub-waveguide adopted a graded waveguide form, achieving good TE performance within the operating bandwidth of 22GHz-40GHz. 21 While it exhibits good mode coupling, it has a high number of higher-order modes within its operating frequency band, and its sum-difference isolation is only 15dB, far from meeting the requirements of engineering applications. It can be used as a broadband coupling TE. 21 An exploration of models.

[0007] From the aforementioned publicly available patents and articles, it can be seen that TE currently... 21 Improvements to mode couplers are mainly reflected in their compact structure and small size, and further research is being conducted on the bandwidth used by the couplers. Summary of the Invention

[0008] The purpose of this invention is to provide an ultra-wideband high-performance TE 21 This invention relates to a differential-mode coupler, which boasts numerous advantages such as wide differential-mode coupling bandwidth, high sum-difference isolation, low insertion loss in the sum channel, low VSWR, large power capacity, and strong scalability. It also solves the problems associated with TE... 21 Broadband tracking problem with a modal operating bandwidth of around 1.8:1.

[0009] The objective of this invention is achieved as follows:

[0010] A broadband dual-ridge waveguide TE21-mode coupler includes a waveguide body, a sub-waveguide cover plate 2, and an absorbing load 3;

[0011] The waveguide body is a cylindrical structure with an inner wall that serves as the main waveguide and an outer wall with a circular array of pillars. The extension direction of the pillars is parallel to the central axis of the waveguide body. An output module is fitted at the bottom of the waveguide body. The output module has a circular array of rectangular slots on its upper part, and the rectangular slots correspond one-to-one with the gaps between two adjacent pillars.

[0012] The sub-waveguide cover plate is placed between two adjacent columns. A matching block is provided at the bottom of the sub-waveguide cover plate, and the matching block fills the top of the corresponding rectangular groove. The cavity between the sub-waveguide cover plate and its two adjacent columns forms the double-ridge loading area of ​​the sub-waveguide cavity. The upper half of the rectangular groove is filled with matching blocks to form the stepped transformation area. The double-ridge loading area and the stepped transformation area are transitioned by a 90° H-plane chamfer area.

[0013] The absorption load is located in the upper region between the inner wall of the sub-waveguide cover plate and the outer wall of the waveguide body, forming a load absorption region.

[0014] Furthermore, the main waveguide is a circular waveguide.

[0015] Furthermore, the center of the circular array of the column is located on the central axis of the waveguide body.

[0016] Furthermore, the central axis of the waveguide body, the rectangular groove, and the gap between two adjacent columns are located in the same vertical plane.

[0017] Furthermore, the load absorption region 121, the double-ridge loading region 122, the 90° H-plane chamfer region 123, and the step transformation region 124 are sequentially connected to form a complete sub-waveguide cavity.

[0018] Furthermore, the 90°H-plane chamfered area has a stepped structure.

[0019] Furthermore, the double-ridge loading region is provided with multiple coupling holes that connect to the main waveguide; the multiple coupling holes are arranged along the central axis of the main waveguide.

[0020] Furthermore, the stepped transformation region 124 filled with matching blocks realizes the impedance transformation from the double-ridged waveguide to the standard rectangular waveguide.

[0021] Furthermore, the outer surface of the column is a double-faceted structure with an obtuse angle, and the adjacent facets of two adjacent columns are located on the same plane; the sub-waveguide cover plate covers the corresponding facets.

[0022] Furthermore, there are 8 columns, 8 rectangular slots, 8 cover plates, 8 load-absorbing blocks, and 8 matching blocks. The number of rectangular slots, 8 cover plates, 8 load-absorbing blocks, 8 matching blocks, and the gap between two adjacent columns are all in one correspondence.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. In this invention, TE 21 The sub-waveguide of the mode coupler adopts a double-ridge loading configuration. The single-mode operating bandwidth of the double-ridge waveguide is much larger than that of a conventional rectangular waveguide. The double-ridge waveguide is used as the TE... 21 The sub-waveguide configuration of a mode coupler can broaden its coupling bandwidth.

[0025] 2. The coupling hole distribution of this invention is optimized by matching with the double-ridge loaded waveguide, which greatly improves the differential mode coupling and makes the secondary waveguide channel have a high degree of suppression on the main mode.

[0026] 3. This invention optimizes the structural design by dividing the coupler into three parts: coupler cavity assembly 1, secondary waveguide cover plate assembly 2, and absorption load assembly 3, which reduces the difficulty of processing and manufacturing and facilitates mass production. Attached Figure Description

[0027] Figure 1 The TE of this invention 21 A schematic diagram of the overall structure of the mode coupler;

[0028] Figure 2 TE in this invention 21Exploded view of the overall structure of the mode coupler;

[0029] Figure 3 This is a schematic diagram of the coupler cavity assembly structure in this invention;

[0030] Figure 4 This is a schematic diagram of one side of the sub-waveguide cover plate in this invention;

[0031] Figure 5 This is a schematic diagram of the structure on the other side of the sub-waveguide cover plate in this invention;

[0032] Explanation of reference numerals in the attached figures: Coupler cavity assembly—1, Sub-waveguide cover plate assembly—2, Coupling hole assembly—3, Main waveguide—11, Sub-waveguide cavity assembly—12, Coupling hole assembly—13, Load absorption area—121, Double ridge loading area—122, 90° H-plane chamfer area—123, Step transformation area—124, Absorbing load slot—21, Cover plate—22, Step matching area—23. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0034] Broadband dual-ridge waveguide TE 21 The mode coupler includes a coupler cavity assembly 1, a sub-waveguide cover plate assembly 2, and an absorption load assembly 3.

[0035] Furthermore, the coupler cavity assembly 1 is composed of a main waveguide 11, a secondary waveguide cavity assembly 12, and a coupling hole assembly 13.

[0036] Furthermore, the main waveguide 11 is in the form of a circular waveguide.

[0037] Furthermore, the sub-waveguide cavity assembly 12 consists of eight sub-waveguide cavities with the same structural dimensions, and each sub-waveguide cavity is connected to the main waveguide through a corresponding coupling hole.

[0038] Furthermore, eight sub-waveguide cavities and their corresponding coupling holes are evenly distributed on a circle concentric with the main waveguide 11. The sub-waveguide cavity has a rectangular cross-section, with one narrow side connected to the main waveguide through the coupling hole and the other narrow side being open.

[0039] Furthermore, each subwaveguide cavity includes a load absorption region 121, a double-ridge loading region 122, a 90° H-plane chamfer region 123, and a step transformation region 124. These four regions are connected in sequence to form a complete subwaveguide cavity.

[0040] Furthermore, the coupling aperture assembly 13 also consists of 8 sets of coupling apertures. The coupling apertures are circular, and each set contains 32 coupling apertures. Their diameters conform to the distribution of a raised cosine function. The coupling apertures are located between the bottom narrow sides of the main waveguide and the corresponding sub-waveguide cavity.

[0041] Furthermore, the subwaveguide cover assembly 2 includes eight identical subwaveguide covers, and each subwaveguide cover is connected to the narrow side of the corresponding subwaveguide cavity opening.

[0042] Furthermore, each subwaveguide cover plate includes an absorption load slot 21, a cover plate 22, and a stepped matching area 23.

[0043] Furthermore, each subwaveguide cover plate includes an absorption load slot 21, a cover plate 22, and a stepped matching area 23.

[0044] Furthermore, the absorption load assembly 3 includes 8 identical absorption loads, each of which is located in the load absorption region 121 within the corresponding sub-waveguide cavity, and is fixed in place by the load receiving slot 21 on the sub-waveguide cover plate.

[0045] like Figure 1 , Figure 2 As shown, the present invention mainly consists of a coupler cavity assembly 1, a sub-waveguide cover plate assembly 2, and an absorbing load assembly 3. The coupler is a transmission-type mode-selective coupler, and the higher-order mode coupled from the main channel is the TE in the circular waveguide. 21 Based on its electric field distribution characteristics, this mode can be used as the differential mode in a single-pulse tracking system. The coupler cavity assembly 1 and the sub-waveguide cover plate assembly 2 form a complete coupler transmission cavity. The function of the absorption load assembly 3 is to absorb a small portion of the reverse-transmitted energy, preventing it from oscillating repeatedly within the sub-waveguide cavity and affecting the strength of the differential-mode coupling. The coupler can couple two degenerate TE21 modes whose electric field directions are orthogonal in space. If the eight sub-waveguides are sequentially labeled as sub-waveguide-a, sub-waveguide-b, sub-waveguide-c, sub-waveguide-d, sub-waveguide-e, sub-waveguide-f, sub-waveguide-g, and sub-waveguide-h, then sub-waveguide-a, sub-waveguide-c, sub-waveguide-e, and sub-waveguide-f transmit a complete TE21 mode. 21 In this mode, sub-waveguide-b, sub-waveguide-d, sub-waveguide-f, and sub-waveguide-h transmit another TE orthogonal to it. 21 The pattern. All eight sub-waveguides have identical structural dimensions, therefore the two degenerate TEs... 21 The modes have the same transmission phase, which facilitates the conversion of two linearly polarized TE modes. 21 The mode is synthesized into circular polarization.

[0046] like Figure 3 As shown, the coupler cavity assembly 1 comprises a main waveguide 11, a secondary waveguide cavity assembly 12, and a coupling aperture assembly 13. The main waveguide 11 is a circular waveguide, and the operating mode in the circular waveguide is TE.11 Model, TE 21 Module, high-order module TM 11 Since mode propagation cutoff is required, the approximate range of the main waveguide radius R can be estimated based on the propagation cutoff conditions of each mode in a circular waveguide. Then, using coupled-wave theory, the relationship between the long side a and the short side b of the sub-waveguide and the circular waveguide radius R can be determined.

[0047] The sub-waveguide adopts a ridge waveguide loading configuration between the two wide sides. The double-ridge waveguide is a variation of the rectangular waveguide, structurally similar but also significantly different. Therefore, the dominant mode of the ridge waveguide differs from that of the rectangular waveguide in terms of TE. 10 The mode field structures are not entirely the same. Due to the presence of ridges, additional capacitance is formed inside the waveguide, and the electric field lines become bent. Therefore, in a double-ridged waveguide, not only Ey, Hx, and Hz field components exist, but also Ex and Hy field components. The relative operating bandwidth of the double-ridged waveguide is the dominant mode TE. 10 The cutoff wavelength of the wave and TE 20 The ratio of the cutoff wavelengths of the waves, the relative bandwidth of a double-ridged waveguide can be expressed as W. c =λ CTE10 / λ CTE20 The single-mode operating bandwidth of a double-ridged waveguide is much larger than that of a conventional rectangular waveguide. Therefore, a double-ridged waveguide is used as the TE... 21 The sub-waveguide configuration of a mode coupler can broaden its coupling bandwidth.

[0048] The coupler cavity assembly 1 adopts a configuration where the main waveguide and sub-waveguide are placed in parallel, with multiple apertures in the common connection area. The reason for achieving directional bandwidth broadening through multi-aperture coupling is that the coupling power of multiple apertures in opposite directions can cancel each other out. A certain phase relationship must be satisfied between the aperture spacing to better achieve mutual cancellation of coupling power; otherwise, it will affect the bandwidth of directivity and isolation. The coupling aperture design synthesizes the directional response, which is a function of frequency. The distribution of each aperture can be designed according to the distribution of a raised cosine function. Since the sub-waveguide uses a double-ridge loading configuration, to ensure that the transmission phase constants of the main waveguide and sub-waveguide are the same, the cross-sectional dimensions of the sub-waveguide and the loading ridge dimensions are adjusted, while the coupling aperture distribution function is weighted. The weighting coefficient is between 0.95 and 1.05. Through the above measures, the TE in this invention... 21 The mode coupling bandwidth reaches 1.8:1.

[0049] like Figure 4 and Figure 5 As shown, the stepped matching region 23 of the sub-waveguide cover plate assembly 2 and the stepped transformation region 124 of the sub-waveguide cavity together form a stepped transformation waveguide, realizing impedance transformation from a double-ridge loaded waveguide to a standard rectangular waveguide. The absorbing load slot 21 has the same cross-sectional dimensions as the absorbing load, which fixes the absorbing load to the absorbing end of the sub-waveguide. The absorbing end of the sub-waveguide and the stepped transformation waveguide are located at opposite ends of the sub-waveguide.

Claims

1. A broadband dual-ridge waveguide TE21-mode coupler, characterized in that, It includes the waveguide body, the sub-waveguide cover plate (2), and the absorbing load (3); The waveguide body is a cylindrical structure with an inner wall that serves as the main waveguide and an outer wall with a circular array of pillars. The extension direction of the pillars is parallel to the central axis of the waveguide body. An output module is fitted at the bottom of the waveguide body. The output module has a circular array of rectangular slots, and the rectangular slots correspond one-to-one with the gaps between two adjacent pillars. The sub-waveguide cover plate is placed between two adjacent columns. A matching block is provided at the bottom of the sub-waveguide cover plate, and the matching block fills the top of the corresponding rectangular groove. The cavity between the sub-waveguide cover plate and its two adjacent columns forms the double-ridge loading area of ​​the sub-waveguide cavity. The upper half of the rectangular groove is filled with matching blocks to form the stepped transformation area. The double-ridge loading area and the stepped transformation area are transitioned by a 90° H-plane chamfer area. The absorption load is located in the upper region between the inner wall of the sub-waveguide cover plate and the outer wall of the waveguide body, forming a load absorption region.

2. The broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The main waveguide is a circular waveguide.

3. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The center of the circular array of the column is located on the central axis of the waveguide body.

4. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The central axis of the waveguide body, the rectangular groove, and the gap between two adjacent columns are located in the same vertical plane.

5. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The load absorption region (121), the double-ridge loading region (122), the 90° H-plane chamfer region (123), and the step transformation region (124) are connected in sequence to form a complete sub-waveguide cavity.

6. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The 90° H-plane chamfer area has a stepped structure.

7. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The double-ridge loading region has multiple coupling holes connected to the main waveguide; the multiple coupling holes are arranged along the central axis of the main waveguide.

8. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The stepped transformation region (124) filled with matching blocks realizes the impedance transformation from a double-ridged waveguide to a standard rectangular waveguide.

9. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, The outer surface of the column is a double-folded surface with an obtuse angle, and the adjacent folded surfaces of two adjacent columns are located on the same plane; the sub-waveguide cover plate covers the corresponding folded surface.

10. A broadband dual-ridge waveguide TE21-mode coupler according to claim 1, characterized in that, There are 8 columns, 8 rectangular slots, 8 cover plates, 8 load-absorbing blocks, and 8 matching blocks. The rectangular slots, 8 cover plates, 8 load-absorbing blocks, 8 matching blocks, and the gaps between adjacent columns are all in one place.

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