Measurement of end-hat effects in a crossed-field amplifier

A linear format, low frequency (150 MHz), low power (10 to 100 W), crossed-field amplifier is operated with variable bias, electrostatic confining electrodes (end-hats). The end-hat bias is found to cause electron transport only in the vicinity of the end-hats. End-hat current measurements indicate a substantial part of the electron beam current (40%) can be collected when the end-hats are biased more positive than the floating potential. The observed change in gain versus end-hat bias can be accounted for by the lost beam current. Device gain versus sole bias measurements have been compared with numerical simulations and give general agreement.<>