High-Efficiency Millimeter-Wave CMOS Oscillator Design Using Port Voltage/Current Optimization and T-Embedding Networks

• Published in: IEEE transactions on terahertz science and technology Vol. 12; no. 6; pp. 550 - 564
• Main Authors: Wang, Hao, Chen, Jingjun, Zhang, Li, Liu, Xiaoguang
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.11.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Circuit design; CMOS; Comparative studies; Complimentary metal-oxide semiconductor (CMOS); Design optimization; Efficiency; Embedding; Logic gates; millimeter wave (mmW); Millimeter waves; Optimization; Optimized production technology; oscillator; Oscillators; Passive components; Power amplifiers; Power generation; signal generator; submillimeter wave; Terahertz (THz); transformer; Voltage
• ISSN: 2156-342X; 2156-3446
• DOI: 10.1109/TTHZ.2022.3186438

We present an optimization-based design methodology for high-power and high-efficiency millimeter-wave fundamental oscillators in CMOS. The optimization is formulated to take into account the loss of the passive components to result in an optimal circuit design. Compared with previous methods, the proposed approach can produce the final design in a single pass of optimization with a fast and robust convergence profile. In this article, we also present a comparative study between the T- and the <inline-formula><tex-math notation="LaTeX">\Pi</tex-math></inline-formula>-embedding networks and show that T-embedding is superior to <inline-formula><tex-math notation="LaTeX">\Pi</tex-math></inline-formula>-embedding in terms of flexibility in biasing and sensitivity to component <inline-formula><tex-math notation="LaTeX">Q</tex-math></inline-formula>. As such, we argue that our design approach can target high output power and high efficiency separately to result in an optimal design for a given application. A design example of a 215-GHz fundamental oscillator in a 65-nm CMOS technology is presented to demonstrate the effectiveness of the proposed design approach. The oscillator achieves 5.17-dBm peak output power at 1.2-V supply with a corresponding dc-to-RF efficiency 12.3% and a peak efficiency of 13.7%. The measured phase noises are <inline-formula><tex-math notation="LaTeX">-90.0</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">-116.2</tex-math></inline-formula> dBc/Hz at 1 and 10 MHz offset, respectively. A second design example at 310 GHz also demonstrates state-of-the-art performance with a peak output power of <inline-formula><tex-math notation="LaTeX">-4</tex-math></inline-formula> dBm and dc-to-RF efficiency of 3.2%.