Development program for a 200 kW, CW 28 GHz gyroklystron. Quarterly report No. 15, October-December 1979

The objective of this program is to develop a microwave oscillator capable of producing 200 kW of CW power at a frequency of 28 GHz. In addition, it is intended that the program will serve as the first step toward development of a device to produce a similar power level at a frequency of 60 and 110 GHz. Feasibility for the 60 and 110 GHz designs will be demonstrated, whenever practical, in the design of the 28 GHz device. Tunability or bandwidth is not considered an important parameter in the design, but efficiency is. Mode purity in the output waveguide is not a requirement for the device, but the circular TE mode is considered desirable because of its low loss properties. With these objectives in mind, the decision was made to pursue an approach based on a cyclotron resonance interaction between an electron beam and microwave fields. The detailed arguments leading to this choice are contained in the final report of the preceding study program. The device configuration of particular interest, called a gyrotron, has been discussed in recent literature. It typically employs a hollow electron beam interacting with cylindrical resonators of the TE/sub 0ml/ class.