A Three-pass Band Filter Based on Mid-End Short-Circuit Ladder Impedance Resonator

Abstract

The invention provides a miniature three-passband filter based on a middle-end short-circuit step impedance resonator. The miniature three-passband filter comprises a first intermediate short-circuit step impedance resonator, a second intermediate short-circuit step impedance resonator, a first uniform impedance resonator, a second uniform impedance resonator, an input feeding line and an output feeding line, wherein the first intermediate short-circuit step impedance resonator and the second intermediate short-circuit step impedance resonator are symmetrically arranged, the first uniform impedance resonator and the second uniform impedance resonator are symmetrically arranged, the first intermediate short-circuit step impedance resonator and the second intermediate short-circuit step impedance resonator are arranged at intervals and are cascaded in two-step way, the input feeding line and the output feeding line are respectively coupled to a tap between the first intermediate short-circuit step impedance resonator and the second intermediate short-circuit step impedance resonator, and the first intermediate short-circuit step impedance resonator and the second intermediate short-circuit step impedance resonator are respectively in gap coupling with the first uniform impedance resonator and the second uniform impedance resonator. By the miniature three-passband filter, the characteristic of three-passband filter can be achieved, the filtering requirement of a communication system for three non-adjacent frequency band signals is met, and the miniature three-passband filter has the characteristics of volume miniaturization, simplicity in structure, design flexibility and the like.

Description

technical field [0001] The invention relates to the technical field of microwave communication, and more specifically, relates to a three-pass band filter based on a middle-end short-circuit ladder impedance resonator. Background technique [0002] In recent years, with the rapid development of the modern communication industry, more and more wireless communication devices have been widely used. However, due to the different working conditions of communication equipment, the required communication standards are also different, so the limited frequency resources are becoming more and more tight, and the frequency band used by each communication standard is likely to be divided into several non-adjacent frequency part. Therefore, in an actual communication system, the system often needs to receive signals of several non-adjacent frequencies. If a wireless communication device uses a traditional single-pass filter, the communication device needs a radio frequency front-end de...

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Problems solved by technology

In response to this situation, radio frequency engineers began to study filters with miniaturized multi-passband frequency characteristics. At present, more research is on miniaturized dual-passband filters, but dual-passband filters have gradually failed to meet the requirements of modern communications. demand, and the three-pass band filter currently studied has the disadvantages of large volume and complex structure

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