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Full text release has been delayed at the author's request until May 13, 2025

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A Systematic Low Power, Wide Tuning Range, and Low Phase Noise mm-Wave VCO Design Methodology for 5G Applications

Alzahrani, Saeed A
http://rave.ohiolink.edu/etdc/view?acc_num=osu1578037481545091

Abstract Details

2020, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
The growing demand for operating bandwidth in modern communication and sensing systems coupled with the shift in cellular networks towards mm-Wave 5G and beyond have demanded a need for voltage-controlled oscillators (VCOs) that can simultaneously achieve wide tuning range (TR) and low phase noise (PN). This demand has created a trend in research that explores new techniques for extending VCO tuning range while not sacrificing PN performance. However, challenges exist for designing mm wave VCOs, such as the low-quality factor associated with passive elements and the significant impact of routing parasitics. These challenges bring about a need to innovate the VCO design methodology. Typically, designing wide tuning range LC-VCOs requires the use of a combination of a fine (analog) tuning varactor and a coarse (discrete) digital tuning switched capacitor bank (CDAC) in order to allow tuning across a wide frequency band. The interconnect transmission lines that link the capacitor bank elements are referred to as feedlines, which are proportional to the capacitor bank size. To achieve a wide tuning range in LC-VCOs, a bigger capacitor bank is employed, which leads to the use of long feedlines. Using long feedlines adds more fixed capacitance to the tank, which is mainly due to the interaction between the routing parasitic inductance and the capacitive elements. To account for the impact of these parasitics, a precise consideration of electromagnetic (EM) effects is required. Unfortunately, careful EM modeling is not a trivial task. This is due to the complexity and time-consuming nature of the EM analysis along with the relative immaturity of the integration of EM design tools in the traditional IC design flow. In this work, a detailed analysis of the CDAC and its routing structure is presented, highlighting a major impact on mm-Wave VCOs performance metrics. A robust technique for extending the TR and reducing the PN in an mm-Wave 5G LC-VCO is proposed, analyzed, and experimentally validated with superior TR, PN, power and die area performance. A new layout approach for the coarse tuning capacitor bank is used to cancel a large portion of the LC tank routing capacitance and reduce the associated routing losses, therefore simultaneously improving the TR and PN of the VCO, while also maintaining a robust operation across the operating frequency band. As a proof of concept, a 26.8 GHz VCO with 5-bit digitally-switched segmented CDAC is implemented with the proposed folded routing structure using a 45nm CMOS SOI technology. Compared to a conventional layout structure, the proposed layout method achieves wider TR, and significantly improves the Q-factor and the linearity of the CDAC. The fabricated VCO achieves a TR of 33%, which covers from 21.4 GHz to 31.2 GHz, with a minimum overlap of ~40%. Moreover, it achieves a PN of −105.5 and -97.2 dBc/Hz at a 1 MHz offset at low, and high bands, respectively, while dissipating an average power of 6 mW from a 1V supply, corresponding to an average figure of merit with TR ( FOMT ) of −192.6 dBc/Hz.
Waleed Khalil (Advisor)
Niru Nahar (Committee Member)
Tawfiq Musah (Committee Member)
132 p.
Electrical Engineering
LC voltage-controlled oscillators, millimeter wave integrated circuits, Wide tuning range VCOs, CDAC Linearization, Folded routing , Low phase noise VCOs

Recommended Citations

Citations

  • Alzahrani, S. A. (2020). A Systematic Low Power, Wide Tuning Range, and Low Phase Noise mm-Wave VCO Design Methodology for 5G Applications [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1578037481545091

    APA Style (7th edition)

  • Alzahrani, Saeed. A Systematic Low Power, Wide Tuning Range, and Low Phase Noise mm-Wave VCO Design Methodology for 5G Applications . 2020. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1578037481545091.

    MLA Style (8th edition)

  • Alzahrani, Saeed. "A Systematic Low Power, Wide Tuning Range, and Low Phase Noise mm-Wave VCO Design Methodology for 5G Applications ." Doctoral dissertation, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1578037481545091

    Chicago Manual of Style (17th edition)

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