Numerical and Experimental Investigations of Self-mixing Effect of a Planar Gunn Diode Oscillator

In this paper, we investigate the self-mixing effect of planar Gunn diode oscillators numerically and experimentally. The simulation shows a 4 μm long GaAs-based heterostructure planar Gunn diode can generate not only an oscillation frequency of 27.5 GHz but also a down-converted signal of 2.5 GHz when an external signal of 30 GHz is injected to the diode. The conversion loss varies between 14 dB and 20 dB depending on the biasing condition as well as the amplitude and frequency of the input signal. Experiments confirmed the simulation results. The self-mixing effect of planar Gunn oscillators show a great potential for simplifying RF frontends for millimeter-wave applications such as 5G and beyond communications, radar, and imaging systems.