A Tunable Dielectric Resonator Oscillator with Phase-Locked Loop Stabilization for THz Time Domain Spectroscopy Systems

SUMMARY Precision microwave measurement systems require highly stable oscillators with both excellent long-term and short-term stability. Compared to components used in laboratory instruments, dielectric resonator oscillators (DRO) offer low phase noise with greatly reduced mechanical complexity. To further enhance performance, phase-locked loop (PLL) stabilization can be used to eliminate drift and provide precise frequency control. In this work, the design of a low-cost DRO concept is presented and its performance is evaluated through simulations and measurements. An open-loop phase noise of − 107 . 2dBc / Hz at 10kHz offset frequency and 12 . 8GHz output frequency is demonstrated. Drift and phase noise are reduced by a PLL, so that a very low jitter of under 29 . 6fs is achieved over the entire operating bandwidth.