An experimental study of a latched non-reciprocal ferrite phase shifter at X-band

Experimental results of measurements on a nonreciprocal X-band latched ferrite phase shifter for phased array radar antennas are presented. Some geometrical parameters were adjusted in such a way that a fairly optimized phase shifter results. Some aspects of this phase shifter were compared with the theoretical results of a modified twin slab model. Two types of ferrite material were examined. The Mg Mn-type has a rather poor temperature performance and a low peak power threshold. Better temperature performance and a much higher peak power threshold (about 20 times) were obtained with a temperature compensated garnet with a lower 4 pi Ms value. The figure of merit of the phase shifter with a ferrite diameter with optimum temperature performance is about 500-600 C/dB. Due to the lower 4 pi Ms value, about 50% more garnet material is needed for the same saturation differential phase as the Mg Mn ferrite.