Monte Carlo simulation of a millimeter-wave Gunn-effect relaxation oscillator

A large-signal computer simulation of a GaAs millimeter-wave Gunn-effect relaxation oscillator has been developed. This computer simulation utilizes a Monte Carlo computation of the electron distribution behavior rather than relying on an analytical expression for the velocity-field characteristic now known to be inaccurate at millimeter-wave frequencies. Results of this simulation are presented for a 70-GHz fundamental oscillator. The device simulated is consistent with currently produced millimeter-wave designs with an active length of 2.0 µm and doping density of 1 × 10¹⁶cm³. A peak efficiency of 2.4 percent with an output power of 144 mW was determined. The device can be characterized as operating in an accumulation transit mode, but with the proverbial "dead-zone" at the cathode.