Optimized RTD-HBT VCO design based on large signal transient simulations

This paper presents an optimized RTD-HBT single ended voltage controlled oscillator topology with increased tuning range and improved frequency stability at 20 GHz oscillation frequency. By connecting the RTD to the emitter of an HBT, a larger voltage swing at the parallel resonator compared to the direct connection can be achieved. In addition the RTD-capacitance influence on the oscillation frequency can be suppressed efficiently. Transient assisted harmonic balance simulations promise an increased oscillation power by 2 dB and a doubled tuning range of about 3.2 GHz compared to the conventional RTD-HBT circuits.