Power Enhancement of 38 GHz Sheet Beam EIO by Field Optimization

A compact high power extended interaction oscillator (EIO) is studied with an aim to increase its output power. The cavity is designed, so that its transverse mode is TM
11
and the longitudinal mode is 2π and the operating frequency is 38 GHz. The modulating E
z
field is optimized in such a way that it varies ascendingly in the growing z-direction. This gradually growing E
z
-field has been found, to have a positive impact on sheet-beam EIO output performance in terms of its output power P
out
and beam-wave interaction efficiency. To incorporate the negative influence of skin effect and surface roughness on the output performance the conductivity of background material is taken one-fourth of that of pure copper σ
Cu
. After field optimization the final design output power P
out
is predicted to improve from 20.19 kW to 24.98 kW and efficiency is improved from 33% to 40.83%.