Broad-stopband electrically-tunable dual-frequency band-pass filter

Abstract

The invention provides a broad-stopband electrically-tunable dual-frequency band-pass filter comprising a metal microstrip line in the front, a dielectric board layer, a first input / output port, a second input / output port, ground metal vias and a metal coating arranged on the back of the dielectric board layer. The metal microstrip line in the front is composed of a uniform impedance resonator, a short-circuited stub and an input / output coupling line; a variable capacitance diode is loaded between the uniform impedance resonator and the short-circuit stub, forming a tunable structure; the tail end of the short-circuited stub is grounded through the ground metal vias. The broad-stopband electrically-tunable dual-frequency band-pass filter is compact in structure, allows dual-frequency tunable, is low in band-pass internal insertion loss and good in out-of-band rejection and has broad stopband.

Description

technical field [0001] The invention relates to a wide-stop-band electronically adjustable dual-frequency band-pass filter, which belongs to the field of wireless communication systems. While two frequency bands are adjustable, the out-of-band suppression is good, and the filter has a wide stop-band characteristic. Background technique [0002] As a basic component of a communication system, a microwave filter's performance is directly related to the communication quality of the entire system. With the continuous development and progress of wireless communication technology, the frequency bands used by communication systems such as GSM, WLAN, 3G and 4G are all concentrated in the low-frequency part of the radio frequency and microwave frequency bands, making this frequency band particularly crowded. At present, filters that use single-port input and output and can satisfy two or more frequency bands at the same time, due to their good reliability, micro-package, good perform...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the filter of the present invention is to provide a dual-band adjustable frequency band for the traditional multi-band system with large volume, high system cost, and the filter bank composed of multiple single-band filters and a single signal processing frequency band. Pass filter, the adjustable range of its two frequency bands is 200MHz, and produces two transmission zeros, the filter has good out-of-band suppression characteristics, compact structure, and meets the needs of miniaturization. By introducing spur lines on the input and output coupling lines structure, broadening the filter stopband range

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