Abstract
High power and broad-band gyrotron traveling wave tube amplifier (gyro-TWT) was required for advanced radar applications, remote sensing, imaging, and space object identification in 92-94 GHz atmospheric window. As is well known, the operation of gyro-TWT was largely restricted by absolute instability which is a more serious problem to gyro-TWT than to conventional TWT, since gyro-TWT usually operates near the cut off frequency of the waveguide.Beginning from the study of various absolute instabilities in a high-order, TE01 mode, distributed-loss gyro-TWT, a systematic optimization of the performance was then proposed under the zero-drive stable condition. This device is recently designed and currently in operation at UC Davis, which can be taken as an illustration of a guide to achieve high power and broad bandwidth. The optimization processes addressed here can be applied to other gyro-TWT design as well.The development of W-band TE01 mode gyro-TWT is collaboration between NTHU and UC Davis groups. The experimental works are conducted in the United States, while the simulation works are supported by NTHU in Taiwan. The current status on the UC Davis experiments and the corresponding simulation works are reported.