Ultra wide band bandpass filter based on ground defective grounding structure

Abstract

The invention discloses an ultra wide band bandpass filter based on ground defective grounding structure. The bandpass filter comprises a circuit board with micro-strip boards coated on two sides, on the front surface of the bandpass filter and a ground plate on the back surface of the bandpass filter, wherein the circuit board comprises a first coupling micro-strip board and a second coupling micro-strip board which are parallel to each other, the coupling micro-strip board is connected with an input terminal through an input terminal transmission line, the second coupling micro-strip board is connected with an output terminal through an output terminal transmission line; the ground plate comprises a first, second and third inverse S-shaped defective grounding structures, wherein the first inverse S-shaped defective grounding structure is arranged at the center of the space under the first coupling micro-strip board and the second coupling micro-strip board which are parallel to each other on the circuit board, and the second and third inverse S-shaped defective grounding structures are arranged symmetrically on the two sides of the first inverse S-shaped defective grounding structure and separately arranged at the centers of the spaces under the output terminal transmission line and the input terminal transmission line. The ultra wide band bandpass filter based on ground defective grounding structure of the invention is a DGS ultra wide band bandpass filter of which wideband can cover any ultra wide band frequency section (3.1-10.6GHz).

Description

technical field [0001] The invention relates to a filter in the microwave communication field, in particular to an ultra-wideband bandpass filter based on a ground defect type grounding structure. Background technique [0002] With the rapid development of communication technology, people have higher and higher requirements for information transmission system. In this context, ultra-wideband technology has become a research hotspot in the field of communication due to its advantages such as simple system, low cost, low power consumption, fast data transmission speed, and high security. Since the FCC (Federal Communications Commission of the United States) lifted the ban on the spectrum in the 3.1-10.6GHz band in 2002 and enabled it to be applied to ultra-wideband devices, there has been a wave of research on ultra-wideband technology in academia and industrial manufacturing. . The filter plays a very important role in the whole radio frequency UWB circuit system. Its char...

AI Technical Summary

Problems solved by technology

The traditional ground defect structure is generally "dumbbell" or "rectangular". This structure is characterized by the ability to introduce transmission zeros, but its insertion loss is relatively large and the selectivity is poor.

Moreover, the current UWB filter based on DGS is either complicated in design or has a large loss, and the structure is not universal, so it is difficult to conveniently design an UWB filter in any frequency band.

[0005] After reviewing the existing literature by the applicant, it was found that the Chinese patent application "ultra-wideband microstrip filter" (application number: 200610117045.2) uses a combination of high-pass and low-pass filters to achieve the ultra-wideband characteristics of the filter. In this invention, 7 A dumbbell-shaped DGS structure and slot unit has a complex structure and many debugging parameters, making it difficult to design; in addition, the "dumbbell" type DGS has a relatively large insertion loss and poor selectivity, so the maximum in-band filter of this type of filter is The insertion loss reaches -1.5dB, and the out-of-band rejection can only reach below -20dB

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