Avalanche transit-time microwave oscillators and amplifiers

Silicon diode microwave oscillators and amplifiers employing two different diode structures are reported. These diodes employ the avalanche transit-time properties originally discussed by Read. A simple p-n junction has produced 13 mW of CW power at 10.5 Gc/s with 0.5 percent efficiency as an oscillator. A similar diode, when incorporated into a circulator coupled amplifier circuit, produced 30 Mc/s bandwidth with 20 dB of gain. Noise figures in the 50 to 60 dB range were obtained in preliminary measurements. Experimental results with these diodes are shown to be in qualitative agreement with the small-signal theory of Misawa. A double diffused "hyperabrupt" diode has also been fabricated as prescribed by Read. These diodes have produced 19 mW of CW power at 5 Gc/s with 1.4 percent efficiency and 13 mW with 1.5 percent efficiency.