Study Of Equivalent Circuit For Coplanar Waveguide Lumped Element And Discontinuities

The design of modern microwave circuit based on CAD technology can improve the ability ofdesigning complex circuits. Microwave design software integrates some microwave components,which relys on circuit theory. In order to simulate the propagation characteristics of microwavecomponents, it is particularly important to extract a appropriate equivalent circuit.This article introduces the basic concept of the coplanar waveguide and the extraction theorywhich based on the static filed analysis. Extracting equivalent circuit of the coplanar waveguidelumped elements and calculating RCL values. After discusse the impact of the physical dimensionsfor the equivalent circuit component values, we propound some advanced equivalent circuit modelfor slot capacitance, interdigital capacitance and planar spiral inductor. Planar spiral inductor hastwo types of equivalent circuit, π-type and T-type.Coplanar waveguide lumped elements interconnection need discontinuities structures whichplay a role of power allocation. This article analyzes the causes of discontinuity and proposes bothnovel equivalent circuit models for T-Junction and Cross-Junction.This article verifies the feasibility of extraction method by that extract the equivalent circuit forthe cpw lumped elements and discontinuities structures. After compare simulation result ofequivalent circuit with HFSS results and simulation results of integrated model in Ansoft designer,we know the equivalent circuit has high accuracy and reliability.