FDTD Modeling and Analysis of Microstrip Circulators

Abstract

A finite difference time domain (FDTD) simulation model for microwave circuits that includes ferrite loaded regions is applied to the analysis of circulator structures designed in microstrip technology. The relevant theoretical background is described including an FDTD based modelfor magnetizedferrite materiaL The suitability of the model is demonstratedfor several examples with different geometries. For verification the obtained scattering parameters are compared with experimental results. INTRODUCTIONAs mobile communication networks become increasingly important, growing interest is evident in the further enhancement of microwave circuit technology. Microwave circulators have become major multi-purpose components for the design of microwave circuits, as these structures can either be used as circulators, isolators, or single-pole double-throw switches. Modem applications of microwave technology such as mobile communications require circulators with increased bandwidth capabilities and minimized dimensions. The key aspects towards these goals are the integration of matching circuits in the circulator structure and the creation of design approaches that are compatible with monolithic microwave circuits. The conventional circulator