Wide Tuning-Range mm-Wave Voltage-Controlled Oscillator Employing an Artificial Magnetic Transmission Line

A novel technique to extend the tuning range of voltage-controlled oscillators (VCOs) is proposed based on magnetic tuning of a transmission line (TL) resonator. A controllable distributed magnetic coupling in a coplanar strip TL is used to tune the TL parameters in general and the inductance in particular, achieving 222% inductance change of the TL at a center frequency of 60 GHz in order to achieve a wide range of frequency tuning. This technique was implemented with a standard cross-coupled pair oscillator, and an additional varactor. The design was implemented in 65-nm CMOS technology, and achieves a tuning range of 55.1-70.4 GHz (24.6%) with a measured average phase noise of -92.2 dBc/Hz at 1-MHz offset across the entire band. The power consumption is 21.5 mW, including the output buffer. The VCO core area is 50 μm × 155 μm excluding the buffer and 83 μm × 245 μm including the buffer.