A dual-frequency slow wave amplifier

Motivated by the recent invention of the recirculating planar magnetron (RPM) [1], we exploit the possible technique of developing a dual-frequency high power microwave (HPM) amplifier. We first study the multi-spectral output characteristics of a novel slow wave structure (SWS) which consists of both upper and lower periodic vane arrays. The SWS is designed such that the operating frequency of the upper cavities is half of that of lower cavities. We analytically derive the dispersion relation for such a dual-frequency SWS. We compare the analytic solution of the cold-tube dispersion diagram with that obtained from the ANSYS HFSS code. Excellent agreement is obtained. The beam-circuit interaction of an injected electron beam is analyzed.