CN-122021523-A - Design and implementation method of novel electromagnetic hybrid coupling filter

CN122021523ACN 122021523 ACN122021523 ACN 122021523ACN-122021523-A

Abstract

The invention discloses a design and implementation method of a novel electromagnetic hybrid coupling filter. The method comprises the steps of firstly determining a transmission zero point target frequency according to indexes, synthesizing a coupling matrix containing non-resonant coupling, then designing an electromagnetic hybrid coupling unit, establishing a mapping model of physical parameters and coupling coefficients, then realizing coupling topology of a filter, particularly a direct coupling path of a source and a load by using the unit, and finally accurately realizing filter response through parameter extraction and iterative optimization. The invention has the core that the transmission zero point can be accurately and flexibly generated at the designated frequency through active design and regulation and control of electromagnetic hybrid coupling, particularly source-load coupling, so that higher frequency selectivity is realized by fewer resonant cavities, the performance of the filter is obviously improved, and the size of the filter is optimized.

Inventors

WEI XINGYI
XIA MIN
LIU FANGLING
CHEN HEHUI
LIU DAN

Assignees

湖南澳德信息科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260205

Claims (8)

1. The design and implementation method of the novel electromagnetic hybrid coupling filter is characterized by comprising the following steps: s1, defining filter performance indexes, wherein the filter performance indexes comprise center frequency, bandwidth, return loss and target frequency of at least one transmission zero point; S2, constructing a comprehensive coupling matrix, and generating a non-resonant node coupling matrix containing direct coupling of a source and a load by adopting a filter comprehensive theory, wherein the coupling matrix defines electric coupling coefficients and magnetic coupling coefficients among resonators, between the source and the resonators and between the load and the resonators; S3, modeling an electromagnetic hybrid coupling structure, and designing an electromagnetic hybrid coupling unit, wherein the electromagnetic hybrid coupling unit is formed by a capacitive coupling component and an inductive coupling component in a parallel or cascade mode, and an analytic relation model or an electromagnetic simulation model of physical structure parameters, coupling coefficients and external quality factors of the electromagnetic hybrid coupling unit is established; S4, realizing a filter topological structure, configuring the electromagnetic hybrid coupling unit in a coupling path between resonators, constructing a direct coupling path between a source and a load without any resonator by adopting an independent electromagnetic hybrid coupling unit, and further generating a designated transmission zero point at a preset target frequency; S5, carrying out parameter extraction and iterative optimization, wherein the method specifically comprises the following steps: S5.1, simulating an initially designed filter model through electromagnetic simulation software to obtain the frequency response of the initially designed filter; S5.2, reversely pushing out an actual coupling matrix from the frequency response by utilizing a parameter extraction algorithm; S5.3, comparing the actual coupling matrix with the target coupling matrix, and adjusting an analytic relation model or an electromagnetic simulation model of physical structure parameters, coupling coefficients and external quality factors of the electromagnetic hybrid coupling unit according to the difference between the actual coupling matrix and the target coupling matrix; And S5.4, repeating the operations from S5.1 to S5.3 until the simulation result meets the preset filter performance index requirement.
2. The method for designing and implementing a novel electromagnetic hybrid coupling filter according to claim 1, wherein the coupling matrix is a 4-order matrix formed by using chebyshev functions or generalized chebyshev functions.
3. The method for designing and realizing the novel electromagnetic hybrid coupling filter according to claim 2 is characterized in that the coupling matrix comprises cross coupling terms among resonators, and the cross coupling terms are matched with direct coupling terms of a source and a load to realize transmission zero point positioning.
4. The method for designing and implementing the novel electromagnetic hybrid coupling filter according to claim 1, wherein the resonator is a square microstrip patch resonator, and the square microstrip patch resonator is attached to the surface of the substrate.
5. The method for designing and implementing a novel electromagnetic hybrid coupling filter according to claim 1, wherein the capacitive coupling component is selected from an interdigital capacitor, a slot coupling or a plate capacitor, and the inductive coupling component is selected from an inductive window, a coupling line or a toroidal inductor.
6. The method for designing and implementing a novel electromagnetic hybrid coupling filter according to claim 1, wherein the net coupling coefficient generated by the electromagnetic hybrid coupling unit The following relation is satisfied: Wherein, the method comprises the steps of, Representing the magnetic hybrid coupling strength; Representing the electrical coupling strength, K is a constant related to the structure of the coupling element.
7. The method for designing and implementing a novel electromagnetic hybrid coupling filter according to claim 1, wherein the number of transmission zeros is two, and the transmission zeros are respectively arranged on an upper sideband and a lower sideband of a passband of the filter.
8. The method for designing and implementing the novel electromagnetic hybrid coupling filter according to claim 1, wherein the electromagnetic simulation software is HFSS or CST three-dimensional electromagnetic simulation software, and the electromagnetic simulation software is used for modeling the mapping relation among physical structure parameters, coupling coefficients and external quality factors of the electromagnetic hybrid coupling unit, constructing an initial model of the overall topological structure of the filter and simulating frequency response, simulating electromagnetic hybrid coupling effects, coupling characteristics among resonators and electromagnetic behaviors of a source-load direct coupling path, and outputting complete frequency response data including return loss and insertion loss.

Description

Design and implementation method of novel electromagnetic hybrid coupling filter Technical Field The invention belongs to the technical field of microwave filter design, and particularly relates to a design and implementation method of a novel electromagnetic hybrid coupling filter. Background Microwave filters are key elements of wireless communication systems for filtering out signals of specific frequency bands and suppressing interfering signals. With the rapid development of communication systems towards high frequency, large bandwidth and miniaturization, more stringent requirements are put on the out-of-band rejection capability, roll-off characteristics, passband flatness and other performances of the filter. The existing filter design mostly adopts a single coupling mechanism of pure capacitive coupling (such as an interdigital filter) or pure inductive coupling (such as a hairpin filter), and the signal screening function is realized through conventional coupling among resonant cavities. The traditional design scheme has obvious limitations that the number of resonant cavities is increased to meet the requirements of steep transition zones and high selectivity, so that the size of a filter is increased and the insertion loss is increased, meanwhile, the process of controlling cross coupling to generate transmission zero points is complex, the transmission zero points are difficult to be accurately and predictably arranged at the designated frequency positions, and the high-performance development requirements of a communication system cannot be met. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a design and implementation method of a novel electromagnetic hybrid coupling filter to solve the technical problems that the existing filter has single coupling mechanism, needs to increase the volume and insertion loss caused by increasing the number of resonant cavities to improve the selectivity, and has complex generation of transmission zero points, is difficult to accurately and predictably arrange at a designated frequency position, and realizes the cooperative optimization of high selectivity and miniaturization of the filter. In order to achieve the above objective, the embodiment of the present invention discloses a method for designing and implementing a novel electromagnetic hybrid coupling filter, the method steps include: s1, defining filter performance indexes, wherein the filter performance indexes comprise center frequency, bandwidth, return loss and target frequency of at least one transmission zero point; S2, constructing a comprehensive coupling matrix, and generating a non-resonant node coupling matrix containing direct coupling of a source and a load by adopting a filter comprehensive theory, wherein the coupling matrix defines electric coupling coefficients and magnetic coupling coefficients among resonators, between the source and the resonators and between the load and the resonators; S3, modeling an electromagnetic hybrid coupling structure, and designing an electromagnetic hybrid coupling unit, wherein the electromagnetic hybrid coupling unit is formed by a capacitive coupling component and an inductive coupling component in a parallel or cascade mode, and an analytic relation model or an electromagnetic simulation model of physical structure parameters, coupling coefficients and external quality factors of the electromagnetic hybrid coupling unit is established; S4, realizing a filter topological structure, configuring the electromagnetic hybrid coupling unit in a coupling path between resonators, constructing a direct coupling path between a source and a load without any resonator by adopting an independent electromagnetic hybrid coupling unit, and further generating a designated transmission zero point at a preset target frequency; S5, carrying out parameter extraction and iterative optimization, wherein the method specifically comprises the following steps: S5.1, simulating an initially designed filter model through electromagnetic simulation software to obtain the frequency response of the initially designed filter; S5.2, reversely pushing out an actual coupling matrix from the frequency response by utilizing a parameter extraction algorithm; S5.3, comparing the actual coupling matrix with the target coupling matrix, and adjusting an analytic relation model or an electromagnetic simulation model of physical structure parameters, coupling coefficients and external quality factors of the electromagnetic hybrid coupling unit according to the difference between the actual coupling matrix and the target coupling matrix; And S5.4, repeating the operations from S5.1 to S5.3 until the simulation result meets the preset filter performance index requirement. Further, the coupling matrix is a 4-order matrix formed by using a chebyshev function or a generalized chebyshev function. Furthermore, the coupling matrix comprises cross coupling t