抄録
An adaptively phase-shift controlled self-injection locked VCO is described. A self-injection locking technique is effective to reduce phase noise. However, a conventional self-injection locked VCO has drawbacks of discontinuous frequency sweep which means narrow bandwidth, and large variation of phase noise. Our proposed adaptively phase-shift controlled self-injection locked VCO overcomes these drawbacks by detecting phase-shift of the self-injection feedback and controlling the phase-shift depending on sweep of the oscillation frequency. This paper describes analysis of relationships between the discontinuity and feedback phase-shift of the self-injection locked VCO. In addition, a VCO-IC which includes a Ka-band VCO and a phase detector is designed and fabricated in 0.18um SiGe BiCMOS technology. Measurement results of the proposed self-injection locked VCO using the fabricated IC show the improvement to the drawbacks. In the proposed self-injection locked VCO, the oscillation frequency sweep is continuous and the phase noise variation is less than 5 dB.
