Characterization of W-Band CW Tunnett Diode

GaAs TUNNETT diodes grown by MBE are investigated at W-band frequencies. The diode structure, output power, conversion efficiency and noise behaviour are presented. The maximum cw rf output power is 1S mW with 2% efficiency at 93 GHz. At a frequency of 2S kHz off carrier the FM N/C ratio is -78 dBc/Hz. A minimum noise measure M of 19 dB is obtained at power levels of about 4 mW. For the application as a self-oscillating mixer the minimum detectable signal was measured to be as low as -140 dBm with a conversion gain of 20 dB at -20 dBm output power.