Modelling of mutual coupling in microstrip antenna arrays fed by microstrip line

摘要

The results of modelling of the coupling between the rectangular microstrip patches in linear arraty are presented. The equivalent circuit in form of a combination of the transmission lines stubs is proposed. It is then applied to model the coupling between two subsequent patches and two patches separated by third one. It is shown that such circuit well represents the mutual coupling in the narrow frequency band (4%). The equivalent circuit was applied to examine how the coupling modified the signals in the input ports of the array and as a consequence how the radiation pattern of the array is changed due to the coupling between the patches. Two linear arrays with cocecans radiation pattern were next designed to verify the theory: first which included proposed equivalent circuit and second one without the coupling (reference array). The results of measurements of VSWR and the radiation pattern for both arrays are presented and compared with theory.