Considerations and simulations of subfrequency excitation of series integrated resonant tunneling diodes oscillator

A subfrequency pulse initiation of an oscillator of two series-integrated RTD´s is considered and simulated. A voltage-dependent current source is adopted to separate the input and output power to represent a circulator in simulations. Simulations show, for example, a 100 GHz integrated RTD oscillator can be excited by a 50 GHz pulse with about 1 ns decay time (a characteristic decay time of 0.2 ns) without the DC instability problem, while a voltage ramp of 1 ns rise or fall time is far too slow to initiate such an oscillator. The mechanism that RTD´s are driven by subfrequency into the negative differential resistance (NDR) from the positive differential resistance (PDR) is analyzed in detail. A preliminary analysis of the transition from 50-100 GHz oscillation is also presented