The TUNNETT-Diode as self-mixing oscillator is described. Noise perfor
mance and back-bias-effect are important for this application. A conve
rsion gain of 28 dB and a corresponding minimum detectable signal of -
148 dBm in 1 Hz bandwidth were measured at -20 dBm output power level.
The best achieved value for RTL was 148 dB at a modulation frequency
of 100 kHz.