A Ka-Band VCO Chip with Integrated Dividers Using 1.5V Supply in 130-nm SiGe BiCMOS Technology for Low-Power Radar Sensors

High-frequency LO signal generation blocks take away significant amount of the power budget in radar sensors. The ever increasing demand for highly efficient and battery powered portable applications require low-voltage and low-power oscillators and frequency dividers. This paper presents the design and characterization results of a low-power SiGe BiCMOS VCO chip with integrated dividers at Ka-band which operates with a single supply voltage of only 1.5V still having key performance parameters meeting the modern radar application needs. Despite the limited voltage range the resonant circuit in the Colpitts oscillator core is optimized to provide 2.5 GHz of analog tuning bandwidth. A transformer based Miller compensated amplifier is used as the output buffer to have 6.3 dBm of differential power at 32.8 GHz while the total dc power consumption of the LO signal generation circuits is 27 mW. The integrated divide-by-16 signal chain followed by a two-stage buffer consumes 44 mW providing 0 dBm differential output power sufficient to drive an external PLL. Experimental results confirm that the proposed chip with wide continuous tuning range and integrated low-voltage dividers is promising for highly efficient low-power radar sensors.