A 4-GHz phase shifter MMIC in 0.18-μm CMOS

Liang Hung Lu*, Yu-Te Liao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


This letter presents a tunable phase shifter implemented in a 0.18-μm CMOS process for monolithic microwave integrated circuit (MMIC) applications. By employing active inductors in the synthetic transmission line architecture, the phase shifter exhibits a wide phase control range, low insertion loss, and miniaturized chip area. Characterized by the S-parameter measurement, the fabricated circuit demonstrates an insertion loss less than 1.1 dB within the 360° phase shift while maintaining a return loss better than 10 dB from 3.5 to 4.5 GHz. Due to the absence of distributed elements and spiral inductors, the area of the phase shifter core is 400 × 200 μm 2. To the authors' best knowledge, this is the smallest chip size ever reported for an analog phase shifter at this frequency band.

Original languageEnglish
Pages (from-to)694-696
Number of pages3
JournalIEEE Microwave and Wireless Components Letters
Issue number10
StatePublished - 1 Oct 2005


  • Active inductors
  • Low insertion loss
  • Regulated cascode
  • Synthetic transmission lines
  • Tunable phase shifters
  • Wide tuning range

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