CMOS quadrature VCO using the injection MOSFET coupling.

This article presents a new quadrature voltage-controlled oscillator (QVCO). The LC-tank QVCO consists of two first-harmonic injection-locked oscillators (ILOs). The outputs of one ILO are injected to the gates of the MOS transistors on the other ILO and vice versa so as to force the two local oscillator (LOs) operate in quadrature. The injection metal-oxide-semiconductor field-effect transistors (MOSFETs) are also used as frequency tuning varactors. The QVCO has been implemented with the Taiwan Semiconductor Manufacture Company (TSMC) 0.18 μm complementary metal-oxide-semiconductor (CMOS) technology and the die area is 0.646 mm × 0.841 mm. At the supply voltage of 1.3 V, the total power consumption is 9.58 mW. The free-running frequency is tunable from 5.44 to 5.95 GHz as the tuning voltage is varied from 0.2 to 2.0 V. The measured phase noise at 1 MHz offset is −121.52 dBc/Hz at the oscillation frequency of 5.91 GHz and the figure of merit (FOM) of the proposed QVCO is about −187.14 dBc/Hz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2631-2634, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26363 [ABSTRACT FROM AUTHOR]