Planar compact spiral three-mode filter

Abstract

The invention provides a plane compact spiral three-mode filter, and relates to a microwave filter. The plane compact spiral three-mode filter is provided with a medium base plate, a spiral resonator with two grounded end points, grounding through holes, a T-shaped branch microstrip wire extending from the center of the resonator to the top, a T-shaped branch microstrip wire extending from the center of the resonator to the bottom, a coupling wire, a feeder wire and a grounding plate, wherein the spiral resonator with the two grounded end points, the T-shaped branch microstrip wire extending from the center of the resonator to the top, the T-shaped branch microstrip wire extending from the center of the resonator to the bottom, the coupling wire and the wire are arranged on the upper surface of the medium base plate; the lower surface of the medium base plate is tightly attached to the grounding plate; the grounding plate completely covers the lower surface of the medium base plate; the two end points of the spiral resonator with the two grounded end points are connected with the grounding plate through the grounding through holes; the grounding plate is externally connected with a coaxial outer conductor; one end of the feeder wire is connected with the end point of the coupling wire; the other end of the feeder wire is externally connected with a coaxial inner conductor. The design is simple; the structure is compact; the center frequency and the passband are adjustable; the manufacturing and the popularization are easy.

Description

technical field [0001] The invention relates to a microwave filter, in particular to a plane compact spiral three-mode filter based on a double T-shaped branch center-loaded and grounded at both ends. Background technique [0002] In recent years, with the rapid development of wireless communication systems and microwave network technology, modern communication technology has put forward higher and higher requirements for high-quality signal transmission and integrated miniaturized circuit design. As an important filter element of the RF front-end, the filter's selection characteristics and suppression characteristics for different frequency microwave signals directly determine the quality of the communication system. The spectrum of electromagnetic waves is limited and needs to be allocated according to actual applications; and filters can be used to limit the radiation of high-power transmitters within the specified frequency band, which in turn can prevent the receiver fr...

AI Technical Summary

Problems solved by technology

However, due to the existence of high-order modes, the design and miniaturization of three-mode and multi-mode filters are particularly difficult. The filter's low insertion loss, high quality factor, passband flatness, and stopband suppression performance have become huge challenges.

Images