Sensors (Sep 2018)

Planar Inverted-F Antenna (PIFA) Using Microfluidic Impedance Tuner

  • Minjae Lee,
  • Sungjoon Lim

DOI
https://doi.org/10.3390/s18103176
Journal volume & issue
Vol. 18, no. 10
p. 3176

Abstract

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This paper proposes a microfluidic impedance tuner that is applied to a planar inverted-F antenna (PIFA). The proposed microfluidic impedance tuner is designed while using a simple double-stub and the impedance is changed by tuning the stub length. In this work, the stub length can be tuned by injecting a liquid metal alloy to the microfluidic channels. Initially, the PIFA operates at 900 MHz with impedance matching of 50 Ω. The impedance is mismatched when a hand is placed close to the antenna. The mismatched impedance is matched to 50 Ω by injecting the liquid metal alloy. The antenna is fabricated on the FR-4 substrate, and the impedance tuner is fabricated on polydimethylsiloxane (PDMS). In order to inject the liquid metal alloy, a piezoelectric micropump and microprocessor are used in the measurement. At 900 MHz, the return loss is successfully tuned from 4.69 dB to 18.4 dB when a hand is placed 1 mm above the antenna.

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