Broadband band-pass filter based on spiral defected ground

Abstract

The invention discloses a broadband band-pass filter based on a spiral defected ground. The broadband band-pass filter based on the spiral defected ground is obtained through a micro-strips and comprises a micro-strip substrate, a bottom ground and a top micro-strip circuit, wherein line troughs which are in odd symmetry about the center and are mutually nested are formed in the bottom ground, the line troughs are respectively of a spiral structure, two spiral trough lines which are in odd symmetry about the center and are nested with each other in a coupling mode are formed in each wiring duct, and a trough line resonator of a spiral structure is formed by every two corresponding spiral trough lines; the top micro-strip circuit comprises an input tap, an output tap, a first stepped impedance feeder and a second stepped impedance feeder, the first stepped impedance feeder and the second stepped impedance feeder correspond to the peripheral trough lines of the mutually nested spiral trough lines in the bottom ground, and the first stepped impedance feeder and the second stepped impedance feeder in the top micro-strip circuit are coupled with the trough line resonators of the bottom ground so that a resonant model can be stimulated. The broadband band-pass filter based on the spiral defected ground is simple and compact in structure and high in band-passing property and band-stopping property, and microwave circuit integration can be achieved conveniently.

Description

technical field [0001] The invention relates to the technical field of microstrip filters, in particular to a wideband bandpass filter based on a spiral defect ground. Background technique [0002] Filters are important passive components that are indispensable for suppressing interfering signals in wireless communication systems. With the rapid development of wireless communication, the requirements for communication channel capacity are increasing day by day, and it is necessary to use broadband filters for broadband signal processing to improve the channel capacity of the entire system. [0003] In microwave / RF equipment for communications, bandwidth is usually expressed in Hertz (Hz). From the perspective of bandwidth, a relative bandwidth greater than 20% or an absolute bandwidth greater than 1GHz is a broadband filter. Among them, relative bandwidth BW=(f 2 -f 1 ) / f 0 . f 2 and f 1 are the upper and lower cut-off frequencies of the passband, f 0 is the center ...

AI Technical Summary

Problems solved by technology

[0007] In view of this, the main purpose of the present invention is to provide a kind of broadband bandpass filter based on spiral defects, to solve the inevitable order increase problem when traditional microstrip filters realize wider bandwidth, and then realize wider bandwidth

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