OPERATION AND OPTIMIZATION OF GATED FIELD-EMISSION ARRAYS IN INDUCTIVE OUTPUT AMPLIFIERS

In an inductive output amplifier, an emission-gated electron beam indu ces high-frequency fields in an output circuit via displacement curren t, not convection current. Emission-gated electron beams experience st rong interactions when traversing a resonant or synchronous electromag netic field, and this strong interaction is responsible for both the i nteresting nonlinear physics and the attractive efficiency and compact ness of emission-gated amplifiers, Field emission cathodes, due to the ir extremely low electron transit time and high transconductance, offe r the opportunity to extend the advantages of emission gating into C a nd X band. This paper presents design criteria for the joint optimizat ion of the held emission array (FEA) structure and the RF input and ou tput circuits of inductive output amplifiers, We find that while outpu t circuits yielding net efficiencies of 50% or greater are well within the state of the art, the gain is likely to be moderate (10-20 dB), W ith today's FEA performance, a desirable operating regime is achievabl e, yielding a new class of compact, highly efficient, and moderate gai n power booster amplifiers.