CN-116435744-B - Slow wave patch resonant cavity, band-pass filter and design method

CN116435744BCN 116435744 BCN116435744 BCN 116435744BCN-116435744-B

Abstract

The invention provides a slow wave patch resonant cavity, a band-pass filter and a design method. The method comprises the steps of sequentially stacking and distributing a first metal layer, a first medium substrate, a patch layer formed by a metal patch array, a second medium substrate and a second metal layer to form a 5-layer structure, wherein the whole structure of each layer is rectangular, a metallized via hole array is formed in the second medium substrate, and the patch layer and the second metal layer are connected by utilizing the metallized via hole array, so that a slow wave patch resonant cavity is formed between the 5-layer structure. Based on this, different types of bandpass filters can be obtained by etching different slot lines in the first metal layer and setting different feed line excitations.

Inventors

ZHANG DEWEI
ZHANG YI
WEI JINJIN
LIU QIKUN
QIAN XING
LIU QING
ZHOU DONGFANG
MA BENHUA
LV DALONG
ZHANG YI
XU HONGHUI
AN NA

Assignees

中国人民解放军战略支援部队信息工程大学

Dates

Publication Date: 20260505
Application Date: 20230530

Claims (9)

1. The design method of the slow wave patch resonant cavity is characterized by comprising the following steps of: sequentially stacking and distributing a first metal layer, a first medium substrate, a patch layer formed by a metal patch array, a second medium substrate and a second metal layer to form a 5-layer structure, wherein the whole structure of each layer is rectangular; The method comprises the steps of forming a metallized via hole array in a second medium substrate, connecting a patch layer and a second metal layer by utilizing the metallized via hole array, forming a slow wave patch resonant cavity between 5 layers of structures, laminating the patch layer and the second medium substrate to be called as a slow wave layer, realizing the tunability of the slow wave patch resonant cavity under the condition of not changing the size of the whole resonant cavity by adjusting the distribution or the size of patches and metallized via holes in the slow wave layer, effectively realizing miniaturization, and adjusting the height of the second medium substrate layer to adjust the cut-off frequency of the resonant cavity.
2. The method of claim 1, wherein the two slot lines are parallel to two adjacent edges of the first metal layer.
3. The method of claim 1, wherein the two slot lines are parallel to two diagonal lines of the first metal layer, respectively.
4. A slow wave patch resonator obtained by the design method as claimed in any one of claims 1 to 3.
5. The band-pass filter based on the slow wave patch resonant cavity is characterized by comprising a resonant cavity unit and two port feeder lines, wherein the resonant cavity unit adopts the slow wave patch resonant cavity formed by the design method as set forth in claim 2, and the two port feeder lines are respectively arranged at non-central positions of a group of opposite sides of the first metal layer so as to be connected into the resonant cavity.
6. The band-pass filter based on the slow wave patch resonant cavity is characterized by comprising a resonant cavity unit and two port feeder lines, wherein the resonant cavity unit adopts the slow wave patch resonant cavity formed by the design method according to claim 3, the two port feeder lines are respectively arranged on a group of adjacent edges of the first metal layer and are connected into the resonant cavity at the position with the distance D from the center point of the edge, and the D is more than or equal to 0.
7. The band-pass filter based on the slow wave patch resonant cavity is characterized by comprising two identical resonant cavity units, a folding ladder impedance coupling line and two port feeder lines, wherein the resonant cavity units adopt the slow wave patch resonant cavity formed by the design method as claimed in claim 2; The port feeder lines are respectively arranged at the non-center positions of the first sides of the first metal layers of the two resonant cavity units, and the non-center positions of the second sides of the first metal layers of the two resonant cavity units are respectively connected with the folding ladder impedance coupling lines; the band-pass filter is wholly symmetrical about the center of the folded ladder impedance coupling line.
8. The band-pass filter based on the slow wave patch resonant cavity is characterized by comprising two identical resonant cavity units, a folding ladder impedance coupling line and two port feeder lines, wherein the resonant cavity units adopt the slow wave patch resonant cavity formed by the design method as claimed in claim 3; The port feeder lines are respectively arranged on the first sides of the first metal layers of the two resonant cavity units and at the positions with the distance D from the center point of the side; the second edges of the first metal layers of the two resonant cavity units are respectively connected with the folding ladder impedance coupling lines at the positions which are distant from the center point of the edges, wherein the first edges and the second edges are adjacent edges, and the D is more than or equal to 0; the band-pass filter is wholly symmetrical about the center of the folded ladder impedance coupling line.
9. The band-pass filter based on the slow wave patch resonant cavity is characterized by comprising a first resonant cavity unit, a second resonant cavity unit, a folding ladder impedance coupling line and two port feeder lines, wherein the first resonant cavity unit adopts the slow wave patch resonant cavity formed by the design method according to claim 2, and the second resonant cavity unit adopts the slow wave patch resonant cavity formed by the design method according to claim 3; The port feeder line is arranged at the non-center position of the first side of the first metal layer of the first resonant cavity unit, the port feeder line is arranged on the third side of the first metal layer of the second resonant cavity unit and is positioned at the position with the distance D from the center point of the side, one end of the folding ladder impedance coupling line is connected at the non-center position of the second side of the first metal layer of the first resonant cavity unit, the other end of the folding ladder impedance coupling line is connected at the position with the distance D from the center point of the side on the fourth side of the first metal layer of the second resonant cavity unit, the first side and the second side are opposite sides, the third side and the fourth side are adjacent sides, and the D is more than or equal to 0.

Description

Slow wave patch resonant cavity, band-pass filter and design method Technical Field The invention relates to the technical field of electromagnetic fields and microwaves, in particular to a high-frequency filter, and especially relates to a slow wave patch resonant cavity, a band-pass filter and a design method. Background From "see words like face" to "everything interconnected", people have witnessed a high-speed development of wireless communication systems in recent decades. The high-frequency filter is used as an indispensible common basic component of the wireless communication system, and has the functions of allocating frequency spectrum resources, filtering useless signals, inhibiting interference signals and the like, and is in face of the demands of miniaturization, high power capacity, high selectivity and low cost of the wireless communication system for high-speed development, and stricter requirements are put forward on the aspects of physical topological structure, comprehensive design method, design production process and efficiency, device volume, cost and the like of the filter. It is a necessary trend to study the weight reduction, miniaturization, and high selectivity of a high frequency Band-pass filter (Band-PASS FILTER, BPF) to match the high-speed development of a wireless communication system. In the prior art, a microstrip or substrate integrated waveguide (Substrate Integrated Waveguide, SIW) technology is generally adopted to realize the design of the BPF. For the BPF realized by the single-mode microstrip resonator, although the BPF has a smaller size structure and is easy to realize a plurality of coupling paths or hybrid electromagnetic coupling, and a plurality of finite frequency transmission zeros are introduced to improve the selectivity of the BPF, the development of the BPF is restricted by the problems of low quality factor and power capacity, and the BPF is unfavorable for matching a wireless communication system with high-speed development. For BPF realized by SIW structure, although there is a high Q value, its design is generally realized by a single cavity, which has a problem of oversized size, which is disadvantageous for miniaturization. Although there are designs of small-sized BPFs using incomplete modes (e.g., half-mold cavity, quarter-mold cavity, or even eighth-mold cavity) or multiple modes, SIWs are limited in the range of achieving miniaturization due to the limitation of their structures, and on the other hand, it is not easy to achieve that multiple coupling paths introduce multiple limited frequency transmission zeros to promote their selectivity. In addition, the BPF implemented by the SIW structure generally has the problem of poor passband selectivity and controllability. The filter based on the dual-mode patch resonator has the advantages of wide coverage of working frequency, light weight, lower cost, easiness in integration with other devices and the like, and also has the advantages of good power capacity, high selectivity, relatively high Q value and the like. However, in the prior art, the dual-mode BPF generally has the problems of poor bandwidth adjustability, weak zero controllability and the like, and even if some dual-mode or multi-mode BPFs provide that the dual-mode BPF has certain selectivity, the general adjustable range is narrower. In the face of increasingly demanding high performance wireless communication systems, dual-mode patch filters are required to further promote miniaturization and high selectivity index matching with the current evolving needs. Meanwhile, in the prior art research, most technical researches are only conducted on a single-cavity dual-mode second-order filter, but in practical engineering application, the single-cavity dual-mode second-order filter is difficult to meet the harsh technical indexes of a wireless communication system. Even if a filter with more than three orders is designed by single-cavity multimode, the implementation method is difficult and has high requirements on processing errors. While, for research on implementing a high-order filter based on a single-cavity multimode filter, most avoidance or only proposal is made that the high-order filter can be implemented by a simple cascading mode. In fact, there are major challenges, especially in the cascading problem of dual-mode or multi-mode BPFs. The simple cascading is generally realized through gap coupling, and has the problems of weak coupling among filters, high energy loss and the like, and is not beneficial to exerting the superior performance of the single-cavity filter. Only a few studies have been carried out using coupled line connections, but there is also the problem of an excessive overall size. In the design of realizing the high-order BPF based on the single-cavity multimode (dual-mode and above) filter, the coupling line realizes the effective coupling of the dual cavities, and because of the impedance matching problem, t