A V-Band Buffer-Less, High-Power SiGe Frequency Quadrupler Using a Stacked Transformer Quadrature Hybrid With a Built-In Harmonic Rejection

This letter presents a V-band buffer-less, high-power frequency quadrupler realized in 0.13-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula>m SiGe heterojunction bipolar transistor (HBT) technology. A compact, stacked transformer-based differential quadrature hybrid is proposed, not only for direct power combining at fourth harmonic but also obtaining a built-in harmonic rejection. For output power (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm {OUT}}$</tex-math> </inline-formula>) and conversion gain (CG) boosting, a common-centroid SiGe HBT cascode with a negative Miller capacitance at a common base (CB) SiGe HBT is devised. A prototype attains measured peak <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm {OUT}}$</tex-math> </inline-formula>, efficiency <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\eta $</tex-math> </inline-formula>, and CG of 8.8 dBm, 3.8%, and 4.0 dB at 56 GHz, respectively, with its 3-dB bandwidth (BW) from 52 to 60 GHz and harmonic rejection ratio (HRR) higher than 30 dBc without any lossy output filter.