Three-pass band filter based on four-mode defective ground resonator

Abstract

Disclosed in the present invention is a quad-mode defected ground structure resonator-based triple-passband filter, comprising a PCB dielectric board, a quad-mode defected ground structure resonator, two microstrip feed lines, and a microstrip stepped impedance resonator. The quad-mode defected ground structure resonator comprises a first resonant cell and four second resonant cells; one end of each of the four second resonant cells is connected to one of four ends of the first resonant cell, respectively. Front ends of the two microstrip feed lines separately extend to an edge of the PCB dielectric board to form two ports; the two microstrip feed lines are symmetric about a first central axis; the distance between the tail ends of the two microstrip feed lines is shortened to form a source-load coupling feed structure. The microstrip stepped impedance resonator comprises two third resonant cells and a fourth resonant cell; two tail ends, close to the first central axis, of the two third resonant cells are separately connected to an open end of the fourth resonant cell. According to the triple-passband filter in the present invention, six transmission zeros can be generated, and high passband selectivity and stopband rejection are provided.

Description

technical field [0001] The invention relates to the technical field of radio frequency microwave communication, in particular to a three-pass band filter based on a four-mode defect ground resonator. Background technique [0002] In modern microwave communication systems, bandpass filters (BPF) need to have good selectivity, out-of-band rejection, wide stopband and miniaturized structure. Although the traditional multimode BPF based on loaded resonators has good selectivity, there are many parasitic passbands. A multimode resonator can generate multiple resonance modes through a single resonator. Therefore, the design of microwave devices using multimode resonators can effectively reduce the size of the device. Although multimode resonators have been proposed, they are only used in the design of broadband filters. The pass-band selectivity and stop-band rejection of the band-pass filter in the prior art are not high, which cannot meet the requirements of modern microwave c...

AI Technical Summary

Problems solved by technology

The passband selectivity and stopband rejection of the bandpass filter in the prior art are not high, which cannot meet the needs of modern microwave communication systems

Images