K-Band Low Phase Noise VCO Based on Q-Boosted Switched Inductor

In this article, the development of the K-band low phase noise voltage-controlled oscillator (VCO) based on Q-boosted switched inductor is presented. Compared with the conventional switched inductor, the eddy current will be decreased using a 2-turn secondary coil, and then the dissipated power from the switch on-resistance will also be decreased, leading to a boosted inductor Q at switch ON-state. The equivalent inductance, quality factor, and self-resonance frequency at switch ON/OFF states are analyzed and derived. For comparison, K-band VCOs have been designed and fabricated in a 130nm BiCMOS process with the Q-boosted and conventional switched inductors. Measured results show that the phase noise has been typically improved by 2–5dB at 100 kHz and 1 MHz offset at switch ON-state, using the Q-boosted switched inductor.