Negative-resistance amplifiers using three-terminal Gunn devices

Negative-resistance amplifiers have been realised using three-terminal Gunn devices. Both transmission and reflection amplifiers were made, with the central frequency in the range 100¿540 MHz for the transmission type and in the range 390¿425 MHz for the reflection type. The maximum gain obtained reached about 53dB with a noise figure of about 20dB for a transmission-type amplifier operated at 140 MHz.