Investigations of the double isolator using three-strip ferrite coupled line

The double isolator using sections of the three-strip ferrite coupled line are presented. The device was developed in two different ways: as a cascade of two circulators and as a planar structure containing lumped resistor. The devices were investigated both theoretically and experimentally. In the experiment the integrated structure of planar double isolator produced average reflection losses better than -10 dB in the band from 11 to 14 GHz. The average insertion losses were about -4.5 dB and isolation was better than -16 dB.