Design of wide-band gyro-twystrons for high power millimeter wave radar applications

Summary form only given. The Naval Research Laboratory is currently investigating gyro-twystrons as high-power, wideband sources for millimeter wave radars. For many radar applications, the gyro-twystron configuration represents a suitable compromise between the high power, narrow band gyro-klystron and the lower power, broadband gyro-TWT. A non-linear simulation code was used to design two gyro-twystrons, the first in Ka-band and the second in W-band. For the Ka-band device, the interaction between the TE/sub 01/ mode and a 65 kV, 7 A electron beam with /spl alpha/=1.3 was studied. The rms perpendicular electron velocity spread was assumed to be 4.5%. The simulation results indicate that an output power of 123 kW, corresponding to an efficiency of 27%, can be achieved. The 3 dB instantaneous bandwidth, which extends from 34.6 GHz to 36.2 GHz, is 4.5%. Next, the non-linear code was used to design a W-Band gyro-twystron. The interaction mode was, once again, the TE/sub 01/. A 65 kV, 4 A beam with /spl alpha/=1.3 and an RMS perpendicular velocity spread of 4.5% was used. The simulations show that 34 kW output power, corresponding to 13% efficiency, can be realized with a 3 dB instantaneous bandwidth of 4.3% (91 GHz to 95 GHz). The theoretical bandwidths were obtained assuming a frequency independent bunching parameter.