A fully wafer-level packaged RF MEMS switch with low actuation voltage using a piezoelectric actuator

Jae Hyoung Park, Hee Chul Lee, Yong Hee Park, Yong Dae Kim, Chang Hyeon Ji, Jonguk Bu, Hyo Jin Nam

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


In this paper, a fully wafer-level packaged RF MEMS switch has been demonstrated, which has low operation voltage, using a piezoelectric actuator. The piezoelectric actuator was designed to operate at low actuation voltage for application to advanced mobile handsets. The dc contact type RF switch was packaged using the wafer-level bonding process. The CPW transmission lines and piezoelectric actuators have been fabricated on separate wafers and assembled together by the wafer-level eutectic bonding process. A gold and tin composite was used for eutectic bonding at a low temperature of 300 °C. Via holes interconnecting the electrical contact pads through the wafer were filled completely with electroplated copper. The fully wafer-level packaged RF MEMS switch showed an insertion loss of 0.63 dB and an isolation of 26.4 dB at 5 GHz. The actuation voltage of the switch was 5 V. The resonant frequency of the piezoelectric actuator was 38.4 kHz and the spring constant of the actuator was calculated to be 9.6 N m-1. The size of the packaged SPST (single-pole single-through) switch was 1.2 mm × 1.2 mm including the packaging sealing rim. The effect of the proposed package structure on the RF performance was characterized with a device having CPW through lines and vertical feed lines excluding the RF switches. The measured packaging loss was 0.2 dB and the return loss was 33.6 dB at 5 GHz.

Original languageEnglish
Article number005
Pages (from-to)2281-2286
Number of pages6
JournalJournal of Micromechanics and Microengineering
Issue number11
StatePublished - 1 Nov 2006


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