Compact multi-notch ultra wide band filter based on DGS

Abstract

The invention discloses a compact multi-notch ultra wide band filter based on a DGS. The filter comprises a dielectric substrate, a half-wavelength short-circuit branch microstrip line located in a center of an upper surface of the dielectric substrate, open-circuit branch microstrip lines loaded on two sides of the half-wavelength short-circuit branch microstrip line, a circular defect microstripline loaded right above the half-wavelength short-circuit branch microstrip line, a wide-branch microstrip line loaded above the open-circuit branch microstrip line, a linear insertion coupling microstrip line, a 50-ohm input feeder line, a 50-ohm output feeder line and an open-loop branch defect ground structure located on a grounding plate, wherein the linear insertion coupling microstrip line,the 50-ohm input feeder line and the 50-ohm output feeder line are formed between the open-circuit branch microstrip line and the wide-branch microstrip line. In the invention, a multimode resonatoris coupled with an open-circuit branch knot and the open-loop branch defect ground structure, four trapped waves can be realized, a central frequency of each trapped wave can be changed by adjusting asize of the open-circuit branch knot, an insertion loss in a whole passband is relatively low, an out-of-band characteristic is good, the structure is compact, cost is low, processing is convenient,and integration with other circuits is easy.

Description

technical field [0001] The invention belongs to the technical field of microwave communication, in particular to a DGS-based compact multi-notch ultra-wideband filter. Background technique [0002] Ultra-wideband technology has appeared in the 1950s, but it was mainly used in the military field until the 1990s. In 2002, the US Federal Communications Commission authorized the 3.1-10.6GHz frequency band to be used for commercial communications. This move opened a new door for the commercialization of ultra-wideband technology products, and quickly accelerated the application of ultra-wideband technology in various fields, such as: ultra-wideband technology in the field of intelligent transportation can quickly search and accurately locate targets; imaging ultra-wideband technology It has good obstacle penetration ability; the ultra-wideband technology in the military field has a good signal concealment function; the low-power and low-cost ultra-wideband technology can be used...

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Problems solved by technology

[0004] The ultra-wideband filter designed by the prior art has the following problems: (1) the notch bandwidth is too large, and some useful information is filtered out; (2) the notch depth is insufficient, and the interference signal cannot be completely filtered out; (3) out-of-band suppression The effect is not good, and the frequency mixing phenomenon at the output end of the filter is serious (4) The number of notches is small, and only one interference signal can be filtered out, but all interference signals cannot be filtered out

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