Microwave generation in the reflex triode

In recent experiments at the Harry Diamond Laboratories and at the Naval Research Laboratory¹, intense microwave emission has been observed during reflex triode operation. A fully relativistic, time-dependent one-dimensional simulation code, based on the technique formulated by Birdsall and Bridges², was written to investigate the collective electron oscillations and to predict the microwave energy spectral density. Predicted and measured reflex triode microwave energy spectral densities in the X-band region are in reasonable agreement with one another and confirm the validity of the model. Computer experiments indicate that microwave generation could be greatly enhanced by feeding the radiated energy back into the oscillating space-charge cloud.