A Simple Approach for Equivalent Circuits of Microstrip Bend and Tee Discontinuity Elements

This paper describes a simple approach to find the equivalent circuits of microstrip bend and Tee discontinuity elements which are widely used in microwave circuits. In order to find the equivalent circuit elements, S-parameters obtained through electromagnetic (EM) simulation and simple network analysis theory are adopted instead of conventional difficult electromagnetic equations and/or numerical methods. The EM simulated S-parameters of bend and Tee elements are converted into Z-parameters. Simple network analysis theories are applied to the Z-parameters for finding the equivalent circuit elements. The calculated S-parameters of the extracted equivalent circuits are in good agreement with EM simulation. In addition, the measured S-parameters, which agree well with simulation, are presented to verify the validity of the proposed method.

I. Introduction

Microstrip line elements are widely used in microwave circuits. Especially, bend and Tee (T) discontinuity elements are very frequently adopted. There are equivalent circuit components of microstrip bend and Tee discontinuity elements [1]. Therefore, it is necessary to understand the characteristics and equivalent circuits of microstrip bend and Tee to design microwave circuits with advanced precision.