Full-wave hydrodynamic model for predicting THz emission from grating-gate RTD-gated plasma wave HEMTs

We provide an initial perturbation to the channel, by applying a small E-field pulse of amplitude E_x=10^-3 V/cm at the center. Power emitted due to positive feedback is then recorded at the measurement planes, depicted in Fig. 1b. Shown in Fig. 6a is the simulated emitted spectrum for two devices. Sharp self-sustained oscillations are observed at the plasmonic resonance frequencies. As expected, these resonance frequencies are functions of grating period (L), and the electron density (n). The simulations predict stronger resonances for higher orders at low temperatures, thus higher carrier mobilities (see Fig 6b). Our simulations are able to predict for the first time the terahertz power-emission levels of RTD-gated plasma wave HEMTs.