A Latching Ring-And-Post Ferrite Waveguide Circulator

This paper presents the performance and normalized design parameters for a latching ring-and-post ferrite circulator in waveguide. A C-band circulator has provided an insertion loss of 0.35 dB and a 20-dB isolation bandwidth of 17 percent. When the circulator was matched for higher maximum isolation (50 dB) but narrower bandwidth (10 percent) at room temperature, the 20-dB isolation bandwidth was 7.8 percent across the -40° to +75°C temperature range. Low-loss operation was obtained at pulsed powers up to 7.5 kilowatts, and at least 20 dB of isolation was maintained up to 100 kilowatts. This performance, in conjunction with a switching speed of a fraction of a microsecond, permits the use of these circulators for transmitting-receiving functions in high-reliability RADARs.