Impact of Phase Perturbations on Power Combining Performance of RTD Oscillator Arrays Based on an Equivalent Circuit Model

An equivalent-circuit model is developed to investigate the effects of fabrication-induced phase perturbations on coherent power combining in terahertz resonant tunneling diode (RTD) oscillator arrays. The resonant tunneling and residual excess currents are represented by two nonlinear voltage-controlled current sources, while the slot antenna is modeled as an equivalent RLC resonant network. Fabrication-induced phase perturbations are modeled by introducing controlled variations in the intrinsic capacitance of individual oscillator units. A GaInAs/AlAs RTD oscillator operating at 220 GHz delivers an output power of 74.56 μW, and its simulated current–voltage characteristics agree well with experimental data. The model is subsequently extended to 1 × 2, 2 × 2, and 4 × 4 arrays, yielding output powers of 140.67, 269.71, and 1053.39 μW and combining efficiencies of 94.33%, 90.43%, and 88.30%, respectively. For the 2 × 2 array, increasing the phase perturbation from 0° to 2° reduces the output power from 269.71 μW to 255.32 μW. The proposed model enables the analysis of phase perturbations arising from fabrication-induced variations in individual RTD oscillator units and provides a theoretical basis for the design and optimization of scalable, high-efficiency terahertz RTD oscillator arrays.