On the Design of mm-Wave Self-Mixing-VCO Architecture for High Tuning-Range and Low Phase Noise

摘要

Frequency synthesis at mm-wave range suffers from a severe tradeoff between phase noise (PN) and frequency tuning range (FTR). This work presents the analysis and compares the performance of fundamental-mode voltage-controlled oscillators (F-VCOs) to harmonic-mode VCOs (H-VCOs). It is shown that unlike a mm-wave F-VCO, an H-VCO can simultaneously achieve higher FTR and lower PN. An H-VCO architecture, denoted as self-mixing VCO (SMV), is presented where the VCO core generates both the first and second harmonic and then mixes them together to obtain the desired mm-wave third-harmonic . Use of a Class-C push–push topology as the VCO core enhances the second-harmonic content to improve mixing efficiency, decreases parasitic capacitance, and improves PN. Compared to an F-VCO operating in a mm-wave band at a fundamental frequency that equals , the proposed SMV architecture achieves about higher FTR and a better PN performance. A 52.8–62.5 GHz SMV prototype is designed and implemented in a CMOS process. Measurement results show that the VCO achieves an FTR of 16.8% with a PN of at 1 MHz offset—resulting in an FTR-inclusive figure-of-merit () of while consuming 7.6 mW fro- a 1.2 V supply.