Recent developments in the average power capacity of rotary-field ferrite phase shifters

An air-cooled experimental S-band rotary-field ferrite phase shifter with an average power capacity of 3 kW is described. The increase in average power capacity was achieved without noticeable degradation of RF performance. An equivalent circuit model for thermal analysis is developed. The model parameters are determined by RF and temperature measurements. A comparison of the model parameters with those of a conventional rotary-field device was made, and substantial reductions in the thermal resistances of the experimental unit were noted.<>