BR FET: A Band Rejection FET for Amplifier and Mixer Applications

A new type of GaAs FET device, the Band Rejection FET (BR FET), is presented. It is a dual gate FET with a LC series resonant circuit connected in parallel with the intergate ohmic contact that acts as a band rejection filter. The main applications of this device are band rejection amplifiers and image rejection mixers. As an amplifier, the BR FET has a gain of more than 3 dB at 12 +- 0.4 GHz with 20 dB rejection at 9.5 +- 0.4 GHz. As a mixer, the BR FET permits conversion gain (/spl ges/ 4 dB) with image frequency rejection of over 30 dB.