Experimental Study of a Compact Dual-Frequency Relativistic Transit-Time Oscillator for Time-Division High-Power Microwave Generation in X- and Ka-Band

This article presents a novel dual-frequency relativistic transit-time oscillator (RTTO) based on a compact coaxial nested structure. In this design, the Ka-band RTTO is coaxially nested inside the X-band RTTO sharing a single pulsed power system and an external pulsed solenoid guiding magnetic field. Comprehensive simulations and experimental validations were performed to assess the device’s performance. Under experimental conditions of 470 kV and 0.6 T, the RTTO generates time-division dual-frequency high-power microwave (HPM), achieving 1.40 GW at 8.42 GHz in X-band with a pulsewidth of 48.0 ns, and 0.40 GW at 30.62 GHz in Ka-band with a pulsewidth of 25.0 ns. The experimental results verify stable operation in each frequency band with no mode competition through multiple consecutive shots, confirming its operational reliability. The compact and lightweight design of the RTTO validates a new approach for achieving efficient dual-frequency HPM generation in a single device and demonstrates its applicability in advanced dual-frequency HPM systems.