A Fundamental D-Band VCO in SiGe:C HBT Technology for Next-Generation Automotive Applications

This paper presents a fundamental D-band Voltage Controlled Oscillator (VCO) designed in a SiGe:C HBT technology, featuring a transit frequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{f}_{\mathbf{T}}$</tex> of 300 GHz and a maximum oscillation frequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{f}_{\text{max }}$</tex> of 520 GHz. The VCO operates over a wide frequency tuning range from 114.2 GHz to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$148 \text{GHz}(25.9 \%)$</tex>, optimized for future automotive bands between 122 GHz and 148.5 GHz. Implemented in a fully differential Colpitts topology, the design achieves a peak single-ended output power of 7 dBm and exhibits a measured phase noise of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-94.4 \text{dBc} / \text{Hz}$</tex> at a 1 MHz offset. A buffer stage is integrated after the oscillator to mitigate load pulling. The circuit consumes 327 mW from a 3.3 V supply. These results demonstrate the potential of SiGe:C HBT technologies for future high-performance automotive radar and communication applications.