Coherent Oscillation in a 2-D Resonant-Tunneling-Diode Terahertz Oscillator Array

To generate high-power, high-directivity terahertz (THz) radiation, in this article, we propose and fabricate a 2-D resonant-tunneling-diode (RTD) THz oscillator array. The array is formed by vertically intersected twisted slot antennas, where enhanced combined radiation is achieved through the antiphase coupling between adjacent RTDs. Additionally, the electrode shapes are tailored to mitigate the electric field cancelation, further increasing the output power. Experimental results confirm coherent oscillation in the fabricated 2×2 array, with frequencies reaching up to 513 GHz and output power exceeding 0.4 mW at lower frequencies. Simulation results suggest that scaling up the 2-D array maintains the strong coherent coupling, despite a nonuniform amplitude distribution among the RTDs. This amplitude nonuniformity can be effectively addressed by introducing metal–insulator–metal capacitors. Furthermore, simulations also predict improved directivity with increased array scale, resulting in a low-diffusion, quasi-plane wavefront. The proposed structure holds the potential for advancing the broad application prospects of THz waves.