A Tri (K/Ka/V)-Band monolithic CMOS Low noise amplifier with shared signal path and variable gains

Chia Jen Liang, Ching Wen Chiang, Jia Zhou*, Rulin Huang, Kuei-Ann Wen, Mau-Chung Chang, Yen-Cheng Kuan

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

7 Scopus citations


This paper presents a single-signal-path tri-band (K/Ka/V) variable-gain low noise amplifier (LNA) fabricated in 28-nm bulk CMOS technology. This LNA uses a common-gate input stage with a triple-coupling transformer (TCT) to achieve better impedance matching across three desired bands than those of prior arts and to enable the necessary gm-boosting to suppress undesired noise. Each LNA stage (except the final one) is loaded with a PMOS switched inductor carefully designed to trade off parasitic capacitances/resistances between off/on states. PMOS devices are also used in parallel with switched inductors as variable resistors to realize the variable gain functionality. Accordingly, the load quality factors can be changed to make the LNA power gain adjustable. This LNA consists of six stages and offers variable power gains from -5.5 to 29.9 dB (24 GHz), -5.5 to 32.4 dB (33 GHz), and -11.5 to 22.2 dB (50 GHz) with respective minimum noise figures of 5.63 dB, 4.55 dB, and 5.96 dB. This LNA consumes 25.6 mW from a 1-V supply and occupies 0.22 mm2 without pads in silicon area.

Original languageEnglish
Title of host publicationIMS 2020 - 2020 IEEE/MTT-S International Microwave Symposium
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages4
ISBN (Electronic)9781728168159
StatePublished - Aug 2020
Event2020 IEEE/MTT-S International Microwave Symposium, IMS 2020 - Virtual, Los Angeles, United States
Duration: 4 Aug 20206 Aug 2020

Publication series

NameIEEE MTT-S International Microwave Symposium Digest
ISSN (Print)0149-645X


Conference2020 IEEE/MTT-S International Microwave Symposium, IMS 2020
Country/TerritoryUnited States
CityVirtual, Los Angeles


  • 28-nm CMOS
  • K-band
  • Ka-band
  • Low noise amplifier (LNA)
  • Millimeter-wave (mmWave)
  • Switched inductor
  • Tri-band
  • Triple-coupling transformer (TCT)
  • V-band
  • Variable gain amplifier (VGA)


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