A W-Band SiGe-HBT Colpitts VCO for Millimeter-Wave Applications with an Analog Tuning Range of 12%

The theory, design and implementation of a millimeter-wave (mm-wave) common-collector voltage-controlled differential Colpitts oscillator (VCO) using 130nmSiGe:C BiCMOS technology is presented. The VCO was optimized to provide a wide analog-only (continuous) tuning range of 81 to 91 GHz (11.6%) for high-precision radar applications. The analog-only tuning capability makes use of a single varactor pair which eliminates the need for digital control signals, switched-capacitor banks and peripheral digital control/interface circuitry. Thus, this approach simplifies the design of frequency synthesizers for mmwave applications and increases the robustness of operation. The VCO operates with a 3 V supply voltage and achieves a low power consumption of 60mW including the cascode output buffers. It provides a single-ended output power of 4.3 dBm and a phase noise of-112dBc/Hz at 10MHz offset with a 90.5 GHz oscillation frequency. It has a state-of-the-art figure-of-merit-tuning (FoM
T
) of -179dBc/Hz.