A low phase noise cross-coupled VCO for x-band applications in 0.13μm SiGe BiCMOS technology

Official URL: https://dx.doi.org/10.1109/MWSCAS60917.2024.10658874

This paper presents a low-power low phase noise voltage-controlled oscillator (VCO) in X-band frequencies fabricated in IHP's 130nm SiGe BiCMOS process (ft/fmax of 250/340 GHz). The core of the VCO is based on a cross-coupled (CC) pair. The phase noise performance of the VCO improved by utilizing a passive LC filter in the tail. The VCO employs a varactor linearization technique to increase the tuning range (TR) and further widen TR achieved by using a thick gate oxide MOS varactor and switched capacitor banks. The VCO core is isolated using cascode buffers, allowing proper driving capability. The design achieves phase noise of -119.25 dBclHz at 1 MHz offset at the center frequency and TR of 15.88 %. The circuit occupies a die area, including the output balun and pads, of 2.08mm2 and consumes 28.7mW power.