A Tunable Wideband Frequency Synthesizer Using LC-VCO and Mixer for Reconfigurable Radio Transceivers

This paper proposes a novel wideband LC-based voltage-controlled oscillator (VCO) for multistandard transceivers. The proposed VCO has a core LC-VCO and a tuning-range extension circuit, which consists of switches, a mixer, dividers, and variable gain combiners with a spurious rejection technique. The experimental results exhibit 0.98 to 6.6 GHz continuous frequency tuning with −206 dBc/Hz of FoMT, which is fabricated by using a 0.18 μm CMOS process. The frequency tuning range (FTR) is 149%, and the chip area is 800 μm × 540 μm