Novel design of travelling-wave FET

In the letter we propose a novel travelling-wave FET, in which an additional image gate is placed beside the drain of the FET as a phase velocity synchroniser. Small-signal analysis is given in the light of coupled wave theory and shows that the device is capable of high gain and wide bandwidth amplification. The easy adjustment of phase synchronisation and compability of the conventional FET fabrication technique make it promising for high-frequency distributed amplification.