Maximum Bandwidth Performance for an Ideal Lumped-Element Circulator

Abstract

Abstract-A procedure based on the analytical model of a lumpedelement, crossover circulator has been developed to maximize its operating bandwidth. The procedure considers the circulator as a network and employs the circulation impedance -the load associated with perfect circulation -as a metric to optimize the bandwidth. Using this procedure, we find that a maximum 194% bandwidth can be obtained for an ideal circulator for above-FMR operation. When the same procedure is applied using a simulation model for the 225-400 MHz frequency range, we achieve 125% bandwidth. We have verified this result from the measurement of a fabricated device; the measured data reveals a bandwidth of 129%.