Three-passband cross coupling substrate integration waveguide filter topology structure and filter

Abstract

The invention discloses a three-passband cross coupling substrate integration waveguide filter topology structure. By using the structure of the invention, three-passband response can be realized; according to a cross coupling theory, a controllable transmission zero point is introduced so that an out-band characteristic is greatly improved; three-passband frequency response is realized and simultaneously an out-band suppression degree is increased. The topology structure is irrelevant to a frequency. Therefore, the topology structure can be used under the different frequencies, a filter structure does not need to be redesigned and application is wide. The topology structure comprises 12 resonant cavities. An input port S is arranged in a resonant cavity (1). An output port L is arranged in a resonant cavity (4). The resonant cavity (1) is coupled to a resonant cavity (1') and a resonant cavity (2) respectively. The resonant cavity (1') is coupled to a resonant cavity (1''). The resonant cavity (2) is coupled to a resonant cavity (3) and a resonant cavity (2') respectively. The resonant cavity (2') is coupled to a resonant cavity (2''). The resonant cavity (3) is coupled to the resonant cavity (4) and a resonant cavity (3') respectively. The resonant cavity (3') is coupled to a resonant cavity (3''). A resonant cavity (4') is coupled to the resonant cavity (4) and a resonant cavity (4'') respectively. The resonant cavity (4) is coupled to the resonant cavity (1) in a cross state so as to generate a transmission zero point.

Description

technical field [0001] The invention relates to the technical field of microwave passive devices, in particular to a three-pass band cross-coupling substrate integrated waveguide filter topology and the filter. Background technique [0002] High-Q filters are an important part of microwave and millimeter-wave circuits. Filters designed with traditional metal waveguides and microstrip lines have problems in some aspects. For example, metal waveguides are relatively expensive, and the Q value of microstrip lines Low, it is difficult to meet some of the required technical indicators. Substrate Integrated Waveguide (SIW: Substrate Integrated Waveguide) is composed of periodic metal vias in multilayer microwave integrated circuits. It has the advantages of high quality factor and large power capacity of traditional waveguide filters, and is easy to process, integrate, and low cost. Since the substrate integrated waveguide resonant unit (the basic unit of the filter) is mostly a ...

AI Technical Summary

Problems solved by technology

However, the existing filter cross-coupling theory can only analyze single-passband filters, and is not suitable for multi-passband filters.

This leads to the lack of comprehensive theoretical guidance in the design of multi-passband filters. The passband characteristics (passband frequency, bandwidth) and out-of-band transmission zero position of multi-passband filters cannot be freely designed. The filter structure is related

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