Novel wideband microband coupler based on defect place structure

Abstract

The invention discloses a Broad Band micro-strip coupler based on a defect ground structure. The Broad Band micro-strip coupler comprises a defect ground structure, a microstrip structure signal layer and ports; wherein the defect ground structure comprises a ground layer, an open ring and an interdigital line. The frequencies f0 and f1 of the defect ground structure are determined according to the technical index force factor C, the characteristic impedances Z0 of the terminals, the central frequency fc and the parameter (Epsilon r, h)of the microstrip; f0 is less than fc, and fc is less than f1(as showed in formula I) and the value of f1 / f0 is determined according to the requirement of the broad band; the size of the defect ground structure is determined according to f0, f1 and (Epsilon r, h). The width W, the distance and the length p of the coupled microstrip lines are calculated through simulation software and then are optimized to satisfy design requirements. Compared with conventional directional couplers with parallel coupled lines, the Broad Band micro-strip directional coupler added with a defect ground structure which is provided with an open ring and an interdigital line is effectively increased in work bandwidth and the defect ground structure can improve the coupling factor of the coupler.

Description

technical field [0001] The invention belongs to the technical field of microwave circuit design, and in particular relates to a broadband microstrip coupler. Background technique [0002] A directional coupler is a directional power divider, which is widely used in microwave circuits. In the field of wireless communication which is developing rapidly at present, the directional coupler with planar structure has been more and more widely used. In recent decades, directional coupler schemes with new structures have been proposed in various literatures, among which the microstrip line structure is the most widely used. At the same time, as the bandwidth requirements in the communication field are getting higher and higher, how to develop a broadband directional coupler has become an urgent issue. The bandwidth of the traditional single-section λ / 4 microstrip directional coupler is relatively narrow. In order to improve its directivity and bandwidth, researchers have proposed...

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Problems solved by technology

[0005] The bandwidth of the traditional single-section λ / 4 microstrip directional coupler is relatively narrow, which cannot meet the increasingly higher requirements of the bandwidth in the communication field. In order to solve the problems of the prior art, the purpose of the present invention is to use the Split ring defect grounding structure defect grounding, design of a new broadband coupled microstrip directional coupler

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