35-65-GHz CMOS broadband modulator and demodulator with sub-harmonic pumping for MMW wireless gigabit applications

Jeng Han Tsai*, Tian Wei Huang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)


Sub-harmonic modulator and demodulator are presented in this paper using 0.13-μm standard CMOS technology for millimeter-wave (MMW) wireless gigabit direct-conversion systems. To overcome the main problem of local oscillator (LO) leakage in direct-conversion systems, the sub-harmonically pumped scheme is selected in this mixer design. An embedded four-way quadrature divider is utilized in the sub-harmonic Gilbert-cell design to generate quadrature-phases LO signals at MMW frequency. For broadband applications, a broadband matching design formula is provided in this paper to extend the operational frequency range from 35 to 65 GHz. To improve the flatness of conversion loss at high frequency, high-impedance compensation lines are incorporated between the transconductance stage and LO switching quad of the Gilbert-cell mixer to compensate the parasitic capacitance. The sub-harmonic modulator and demodulator exhibit 6 ± 1.5 dB and 7.5 ± 1.5 dB measured conversion loss, respectively, from 35 to 65 GHz. For MMW wireless gigabit applications, the gigabit modulation signal test is successfully performed through the direct-conversion system in this paper. To our knowledge, this is the first demonstration of the MMW CMOS sub-harmonic modulator and demodulator that feature broadband and gigabit applications.

Original languageEnglish
Pages (from-to)2075-2084
Number of pages10
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number10
Publication statusPublished - 2007 Oct
Externally publishedYes


  • CMOS
  • Demodulator
  • Direct conversion
  • Millimeter wave (MMW)
  • Modulator
  • Sub-harmonically pumped

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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