A novel resonance absorption isolator with T-microstrip

A novel resonance absorption isolator for cellular phone terminals has been developed, which employing T-microstrip line on a ferrite blank. Reduction of stray capacitance of the microtrip makes it possible to realize improvement of the insertion loss and to decrease the additional circuit element number. The operation theory of the isolator has been confirmed by using EM field analysis and circuit simulator. The developed isolator is composed of only two elements which are a 1.0×0.8×0.6mm
³
Core-Isolator and a 0.4×0.2×0.2mm
³
ceramic capacitor. Its insertion loss and isolation performances are 0.5dB max. and 9.2dB min., respectively at 1.9GHz band.