A Ka band BiCMOS LC VCO with wide tuning range and low phase noise using switched coupled inductors
This paper presents a wideband and low phase noise millimeter wave (mm wave) voltage controlled oscillator (VCO) fabricated in 130 nm BiCMOS technology. The output signal can sweep from 29.6 to 35.5 GHz, which corresponds to 18.1% tuning range. The LC tank of the VCO consists of two coupled inductors and a binary weighted varactor bank. The secondary inductor is terminated with a switch realized with heterojunction bipolar transistor (HBT) Depending on the switch state, the effective inductance of the LC core can be changed which leads to significant improvement of tuning range. It is shown that the resistance of the switch in ON state can have a small effect on the LC tank quality factor Q if the switch is properly sized. This results in a good phase noise performance over the whole frequency range. The measured phase noise at 1 MHz offset from the carrier is better than 97 dBc/Hz, which results in a figure of merit of 180 dBc/Hz. The VCO dissipates 20 mW and occupies 0.1mm2 chip area.
2016 11th European Microwave Integrated Circuits Conference (EuMIC)