Average power capacity of rotary-field ferrite phase shifters

The average power capacity of the phase shifter as determined by the increase in rod temperature and the maximum thermal gradient is analyzed. An equivalent circuit model for thermal analysis is developed, and its parameters are determined by RF and temperature measurements. An alternative geometry which results in significantly improved average power capacity without noticeable degradation of RF performance is described. An experimental phase shifter using the alternative technique was built and tested. Comparison with a conventional rotary-field phase shifter demonstrates the improvement achieved