Impatt Power Amplifier for Microwave-Link-System

The paper describes an impatt amplifier with 20 dB gain and 1,6 W output power, which is being used in FM microwave link systems for amplification of RF-Signals. The link system is capable of transmitting 1260 speech channels or one TV signal for long haul applications from 6.4 to 8.5 GHz. A silicon double drift impatt diode is used in an injection locked oscillator mode with 20 dB gain. The FM amplifier is designed in evanescent-mode-waveguide technique and the RF circuit is optimized to achieve the desired locking bandwidth and noise figure using a double tuned circuit. The noise and transmission properties of the amplifier are calculated and compared with the measured response.