Analysis and Design of a Series-Resonance VCO With Magnetic Mutual Resistance

In this article, a series resonance voltage-controlled oscillator (SR-VCO) with magnetic mutual resistance (MMR) is proposed and analyzed for the mm-waveband. The proposed SR-VCO utilizes a single transformer to implement the$LC$-tank. By manipulating the phase shift between the currents in the primary and secondary coils of the transformer, we introduce two resistive impedances, which we refer to as MMRs. Consequently, the power consumption is reduced due to the MMR-enhanced tank impedance. Since the MMR arises from magnetic coupling and does not dissipate energy, the$Q$-factor of the$LC$-tank remains unaffected. Moreover, by lowering the amplitude of impulse sensitivity function (ISF), the proposed MMR suppresses active devices noise, which is a dominant source of phase noise (PN) at mm-wave frequencies. The proposed SR-VCO is fabricated in a 65-nm CMOS technology with$0.06~\text {mm}^{2}$core area. The measured PN is −120.09 dBc/Hz at 1 MHz offset and −142.7 dBc/Hz at 10 MHz offset with a power consumption of 46 mW, corresponding to a FoM of 192.3 and 194.9 dBc/Hz.