Cmos

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1

A 200-GHz Inductively Tuned VCO With 7-dBm Output Power in 130-nm SiGe BiCMOS

Pei-Yuan Chiang, Student Member, IEEE, Omeed Momeni, Member, IEEE, and Payam Heydari, Senior Member, IEEE

Abstract—A highly efficient push–push voltage-controlled oscillator (VCO) with a new inductive frequency tuning topology for (sub) terahertz frequencies is presented. The tuning technique is based on a variable inductance seen at the emitter node of a base-degenerated transistor. The variable inductor exhibits high quality factor and high tuning range due to the tunable transistor transconductance via bias current. Fabricated in a 0.13- m SiGe BiCMOS process, the VCO achieves a tuning range of 3.5% and an output power of 7.2 dBm at 201.5 GHz. The dc power consumption of the VCO is 30 mW, resulting in a high dc to RF power efficiency of 0.6% and a figure of merit of 165, which is the highest FoM for any silicon-based VCO reported to date at this frequency range. To demonstrate the functionality of the tuning technique, three VCO prototypes at different oscillation frequencies, including one operating in the 222.7–229-GHz range, are implemented and measured. Index Terms—Clapp oscillator, Colpitts oscillator, inductive tuning, push–push oscillator, submillimeter wave, terahertz (THz), varactor-less tuning, voltage-controlled oscillator (VCO).

I. INTRODUCTION IGH-FREQUENCY range including (sub) terahertz (THz) and millimeter-wave (mm-wave) presents a great promise for noninvasive active and passive imaging, chemical, and biological spectroscopy, multigigabit wireless communications, and short-range radars [1]–[5]. Towards realization of a high-performance (sub) THz system, one of the most challenging steps is to design a high-power, tunable, and efficient signal source [6]–[8]. A...