A dual-gate MESFET for a high performance UHF TV tuner

This paper demonstrates a new dual-gate GaAs MESFET specially designed for a UHF TV tuner that meets the coming FCC regulation of NF reduction to the same level as the present VHF TV tuner. The device has been designed under the philosophy as follows. (i) To reduce |S11| at the smallest expense of the low noise feature interent in GaAs MESFETs. (ii) To obtain AGC and cross-modulation performances compatible with those of a conventional Si MOS tetrode. The optimized pattern geometry satisfying the above philosophy was obtained through extensive theoretical and experimental studies. The FET was molded in a plastic package. The new FET, of which minimum NF value is as low as 0.9dB. was compatible with a Si MOS tetrode in a conventional tuner circuit owing to the large K value. The AGC and CM performances were also satisfactorily excellent.