A Double-pass Band-Pass Filter Based on Asymmetric Coupled Lines

Abstract

The present invention provides a dual-pass band-pass filter based on asymmetric coupled lines, which includes a dielectric substrate, a filter located on the upper surface of the dielectric substrate, and a metal ground plate located on the lower surface of the dielectric substrate. The filter includes an improved H-type multimode resonator, asymmetric parallel coupling lines loaded on the left and right sides of the multimode resonator, stepped impedance branches loaded on the upper and lower sides of the multimode resonator, parallel three-wire coupling composed of high impedance lines and parallel coupling lines Line, open stub loaded on the underside of the left port feeder. The invention adopts the multi-mode resonator loaded with stepped impedance branches and the strong coupling of the asymmetric coupling line structure, which not only improves the selectivity of the pass band, but also reduces the size of the filter. The insertion loss in the two passbands is low and adjustable, the out-of-band characteristics are good, the structure is compact, the cost is low, the processing is convenient, and it is easy to integrate with other circuits.

Description

technical field [0001] The invention belongs to the technical field of microwave communication, and more specifically relates to a double-pass band-pass filter based on an asymmetric coupled line. Background technique [0002] With the rapid development of modern literature communication technology, more and more mobile communication, satellite communication, radar tracking and remote sensing technology need to rely on microwave and millimeter wave technology, which leads to an increasingly complex electromagnetic environment and ultimately makes spectrum resources more and more tense. [0003] Therefore, in order to effectively utilize more and more frequency channels, and to reduce the volume and weight of communication circuit equipment, the research of dual-band devices has attracted more and more attention. [0004] At present, the design methods for realizing dual-band filtering mainly include: [0005] 1. Use an external impedance matching network to cascade two band...

AI Technical Summary

Problems solved by technology

[0005] 1. Use an external impedance matching network to cascade two bandpass filters with different center frequencies, but this will increase the size and loss of the filter;

[0006] 2. Connect resonators with open or short-circuit stubs in series or in parallel in the broadband bandpass filter, so that a transmission zero point is generated in the passband, thereby obtaining high selectivity, but the design is complicated and the circuit area will be increased at the same time ;

[0007] 3. Using the high-order characteristics of the base-layer waveguide resonator can also design a dual-pass band-pass filter, but the filter is difficult to adjust and has poor flexibility

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