Design of silicon based terahertz transceiver

Abstract

Moving from passive building blocks to the active ones, we also discuss in this thesis a number of key circuit blocks that can be employed in communication system or spectroscopy systems. We cover voltage controlled oscillators (VCO), power amplifiers (PA) and frequency doublers with circuit analysis, design and fabrication. The designed VCO achieves 28% tuning range at 103.5 GHz by switching the emitter transmission lines, and has a peak output power of 4.2 dBm, 5.5\% DC to RF efficiency. To generate high power at frequencies close to or exceeding fmax, a frequency doubler with optimized harmonic reflectors over wide bandwidth is proposed. The analysis is verified by electromagnetic simulation and measurement results. A signal chain formed of a power amplifier followed by a doubler stage is fabricated and a saturated output power of 6.5 dBm at 204 GHz with more than 50 GHz bandwidth is reported. The results are considered one of the highest reported figure of merit for mmWave sources compared to state of the art published results.