Microstrip dual-passband coupling filter

Abstract

The invention discloses a microstrip dual-passband coupling filter which comprises four feeder lines, two open branch lines and six microstrip lines, wherein six microstrip lines form a multi-mode dual-passband resonator for generating dual passband; the microstrip dual-passband coupling filter is of a bilaterally symmetrical structure; two sides of the multi-mode dual-passband resonator are respectively connected with one open branch line; the two open branch lines are respectively connected with the two feeder lines to form interdigital parallel coupled line structures; a connecting structure of the open branch lines and the multi-mode dual-passband resonator is a T-shaped structure; the two interdigital parallel coupled line structures are used as input and output respectively. The microstrip dual-passband coupling filter has high frequency selectivity and isolation, the two passbands can be adjusted independently, and the filter is simple in circuit structure and easy to process.

Description

technical field [0001] The invention relates to microwave transmission technology, in particular to a double-passband filter for microwave transmission, which is a microstrip double-passband coupling filter. Background technique [0002] With the rapid development of microwave transmission technology, multi-band wireless transmission system has become an important part of wireless transmission. In the communication system, as the filtering performance is paid more and more attention, the research of the dual-passband filter is also attracting attention. The performance advantages such as low passband loss, high stopband rejection, adjustable bandwidth, and miniaturization have become important criteria for judging the pros and cons of dual-passband filters. The microstrip structure has great advantages in low cost and easy processing, so the microstrip dual-passband filter has been extensively studied. [0003] In the prior art, two methods are mainly used to realize the d...

AI Technical Summary

Problems solved by technology

The more direct method is to combine several independent low-pass, high-pass or band-pass filters. The filter designed in this way is relatively simple to implement and easy to understand, but it usually takes a lot of money to achieve the designed performance. space

The second method is to use Stepped Impedance Resonators (SIR) to achieve, usually using branch line resonators (SLRs) or ring resonators, but it is difficult to realize because of the strong correlation between resonance frequency and coupling coefficient Independent modulation of the bandwidth of the two passbands

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