200-Megabit pulsed-avalanche oscillation with Ge silver-bonded diode in 50-GHz region

The pulsed operation of an IMPATT diode at extremely high repetition rates of 200 Mbit is accompanied by two problems: (1)-the diode is apt to be destroyed as the operating condition becomes very similar to that of CW operation; and (2)-the time lag between the avalanche oscillation and the input pulse becomes more distinct. The former can be solved by the use of a diode such as the GSB3 which can be operated continuously. The breakdown voltage of this diode ranges from 7 to 11 V. The spectrum width of the avalanche oscillation is observed to be approximately 300 kHz at 50.2 GHz. The spectrum of the locked avalanche oscillation is exactly the same as that of the injected mm-wave which is obtained from a klystron and has a spectrum width of 150 kHz. These results were observed with a spectrum analyzer. From the noise measurement of the avalanche oscillation obtained with this diode, it was observed that the FM noise is very much larger than the AM noise.