Frequency increase in resonant-tunneling diode cavity-type terahertz oscillator by simulation-based structure optimization

Terahertz (THz) radiation, in the range between the light waves and millimeter waves, has gained much attention because of its various promising applications. Resonant tunneling diodes (RTDs) have the potential for use as compact and coherent THz sources operating at room temperature. In this paper, oscillation frequency limitations and structure dependences for a RTD THz oscillator with a cylindrical cavity resonator are analyzed. Based on the dependences of the oscillation frequency on resonant cavity dimensions, a method of the oscillator structure optimization and matching with an RTD structure was proposed. It is revealed that there is only one combination of the resonant cavity dimensions which gives the maximum possible oscillation frequency for this type of structure. Analysis of the calculation results has shown that fundamental oscillation up to 2.77 THz could be expected for the RTD device considered in the present study by using the proposed optimization technique. (c) 2020 The Japan Society of Applied Physics