Design of Submillimeter Schottky Mixers Under Flat-Band Conditions Using an Improved Drift-Diffusion Model

Minimum conversion loss in millimeter and submillimeter-wave Schottky mixers is achieved when the diodes are slightly pushed into the flat-band regime. The discrepancies found between experimental results and physics-based harmonic balance simulations for a 330 GHz antiparallel diode pair subharmonic Schottky mixer showed that traditional drift-diffusion models with conventional boundary conditions at the Schottky contact do not correctly predict the behavior of the Schottky-based mixers working under flat-band conditions. In this work, we employ Monte Carlo simulations to get physical insight of the Schottky diodes working in the flat band regime. New boundary conditions obtained from this analysis have been included in our drift-diffusion simulator which has resulted in an improvement of our circuit simulator to predict mixer operation under flat band regime.