Investigations of a high gain W-band gyro-TWA

This paper presents a numerical investigation of alternate gyrotron Traveling Wave Amplifier (gyro-TWA) configurations for increased gain. Previous experimental results showed a maximum stable gain of 37 dB over the frequency range 90-96 GHz. These results were limited in bandwidth by the input power from the solid-state pre-amplifier. The simplest way to mitigate the limited input power available is to increase amplifier gain. Doing so without inducing instability requires the introduction of losses to the RF circuit. We present PIC simulations contrasting a range of new designs combining two gain stages and lossy elements with results for the single section design presented in our earlier experimental program.