Overmoded traveling wave tubes for MM and THz applications

High power sources of coherent radiation, producing Watts to tens of Watts of average power, are needed for applications in the millimeter wave and THz regimes. Overmoded traveling wave tubes offer the possibility of meeting these requirements in rugged and simple to fabricate devices. Results on a 94 GHz overmoded TWT confirm the viability of this approach. Designs for a PBG amplifier operating at 250 GHz, based on the successful 94 GHz TWT, are described.