Widely tunable THz source based on constructive wave oscillator in a 130-nm SiGe BiCMOS

This paper presents a novel tunable THz source based on a six-section Constructive Wave Oscillator (CWO) designed in a 130-nm SiGe BiCMOS process. Unlike traditional THz source designs that rely on VCOs and frequency multipliers, this approach offers a simple, compact, and yet power-efficient solution. The proposed architecture achieves a 10%\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10 \%$$\end{document} tuning range and generates phasor signals beyond the conventional I/Q (0 degrees\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$0<^>{\circ }$$\end{document}-90 degrees\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$90<^>{\circ }$$\end{document}) type, enabling new possibilities for modulation schemes and harmonic cancellation. The design generates a 0.285 THz signal based on a tunable CWO operating at 95 GHz, with 95 GHz signals distributed along the ring with 60 degrees\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$60<^>{\circ }$$\end{document} phases. The THz source combines these signals to produce a signal at 3f0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$3f_0$$\end{document} using a harmonic cancellation technique. The circuit occupies a compact area of 0.46 x 0.51 mm2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {mm}<^>2$$\end{document} and dissipates only 60 mW of DC power from a 2V supply. The tunable THz source demonstrates a simulated -22 dBm output power and a phase noise of -76 dBc/Hz at a 1 MHz offset, making it a significant advancement in the field of THz signal generation.