A 5-GHz band low-phase noise CMOS VCO using above-IC technologies

This article presents a 5-GHz band low phase noise CMOS voltage controlled oscillator (VCO) based on a high quality factor above-IC inductor that is stacked on the top of a 0.18-μm RF CMOS process using wafer level package technology. The measured phase noise of the VCO is -119.8 dBc/Hz at 1 MHz offset frequency, which is an improvement of 6 dB compared to a conventional VCO with on-chip CMOS inductor. The design challenge of the grounding of the above-IC inductor stacked on the CMOS structure is investigated in this work.