A robust RF MEMS variable capacitor with piezoelectric and electrostatic actuation

T. Ikehashi*, T. Ohguro, E. Ogawa, H. Yamazaki, K. Kojima, M. Matsuo, K. Ishimaru, H. Ishiuchi

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

7 Citations (Scopus)


An RF MEMS variable capacitor using hybrid actuation of piezoelectric and electrostatic forces is presented. A surface micromachining process is used to fabricate the device. The piezoelectric actuator, which uses thin film PZT, enables low voltage actuation while the electrostatic actuator realizes large capacitance ratio. The measured capacitance ratio is Cmax/Cmin=14 at 5V. We demonstrate that the hybrid actuation enables to lower the pull-in voltage without changing the pull-out voltage. We also show that the shift of pull-out voltage due to dielectric charging can be reduced drastically at actuation voltages below 10V. In this sense, the hybrid actuation can realize low voltage operation with enhanced robustness for stiction.

Original languageEnglish
Article number4014812
Pages (from-to)39-42
Number of pages4
JournalIEEE MTT-S International Microwave Symposium Digest
Publication statusPublished - 2006 Dec 1
Externally publishedYes
Event2006 IEEE MTT-S International Microwave Symposium Digest - San Francisco, CA, United States
Duration: 2006 Jun 112006 Jun 16


  • Dielectric charging
  • Piezoelectric actuator
  • Stiction
  • Surface micromachining
  • Variable capacitor

ASJC Scopus subject areas

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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