A broadband phase-locked Ka-band single-tuning VCO with reconfigurable loop filters

A broadband phase-locked oscillator (PLO) based on Ka-band single tuning voltage-controlled oscillator (VCO) module is designed, fabricated and measured. The configuration based on the frequency offset dividing phase-locked loop was realized with a simple VCO module, a phase-locked loop board, and an image-rejection mixer. The locking range of the PLO system covers the whole 4.6 GHz VCO tuning range. An adaptive bandwidth theory is used to overcome problems caused by large variation of the VCO tuning sensitivity and to improve the in-band phase noise of PLO by at least 17 dB. The experimental results show that the in-band phase noise of -96 dBc/Hz at offset frequency of 10 kHz is achieved with the loop bandwidth of 1 MHz. The measured RMS jitter of the PLO at 37.8 GHz is 31 fs for 1 kHz to 100 kHz frequency offset range.