Design of an X-Band CMOS VCO with a Transformer-Coupled and Transconductance-Boosted Stacked Topology

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dc.contributor.authorPeng, Yen Ying
dc.contributor.authorLi, Syu Bin
dc.contributor.authorWang, Sen
dc.contributor.authorPakasiri, Chatrpol
dc.date.accessioned2026-08-06T10:55:33Z
dc.date.available2026-08-06T10:55:33Z
dc.date.issued2026-06-01
dc.description.abstractThis paper presents the design and implementation of an X-band voltage-controlled oscillator (VCO) fabricated in a standard 180-nm CMOS process. To sustain stable oscillation under a constrained power budget, a gm-boosted topology is employed, integrating vertically stacked cross-coupled transistors with a center-tapped transformer to enhance the equivalent negative conductance. The boosting is achieved through two complementary mechanisms: the center-tapped transformer performs an impedance transformation that repurposes the layout parasitic capacitances into transconductance-enhancing elements, while the stacked cross-coupled pair reuses the DC current and suppresses the source-degeneration of a conventional pair, jointly sustaining a robust start-up margin at a low 0.75 V supply. On-wafer measurement results demonstrate a frequency tuning range from 8.78 GHz to 9.13 GHz as the control voltage is swept from 0 V to 1.8 V, with an average VCO gain K<inf>VCO</inf> of 447.5 MHz/V. Under a total DC power consumption of 6.9 mW, the oscillator delivers an output power of 4.54 dBm and exhibits a measured phase noise of −103 dBc/Hz at a 1-MHz offset.
dc.identifier.citationJournal of Low Power Electronics and Applications, 16(2), 2026
dc.identifier.doi10.3390/jlpea16020019
dc.identifier.issn20799268
dc.identifier.other2-s2.0-105043022507
dc.identifier.urihttps://dspace.kmitl.ac.th/handle/123456789/18121
dc.sourceJournal of Low Power Electronics and Applications
dc.subjectlow-phase-noise
dc.subjectlow-power
dc.subjectnegative transconductance boost
dc.subjectvoltage-controlled oscillator (VCO)
dc.subjectX-band
dc.titleDesign of an X-Band CMOS VCO with a Transformer-Coupled and Transconductance-Boosted Stacked Topology
dc.typeArticle

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