Surface acoustic wave resonators for wireless sensor network applications in the 433.92 MHz ISM band

Evangelos Moutoulas*, Muhammad Hamidullah, Themis Prodromakis

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review

Abstract / Description of output

Surface acoustic wave (SAW) resonators are low cost devices that can operate wirelessly on a received radio frequency (RF) signal with no requirement for an additional power source. Multiple SAW resonators operating as transponders that form a wireless sensor network (WSN), often need to operate at tightly spaced, different frequencies inside the industrial, scientific and medical (ISM) bands. This requires nanometer precision in the design and fabrication processes. Here, we present results demonstrating a reliable and repeatable fabrication process that yields at least four arrays on a single 4-inch wafer. Each array consists of four single-port resonators with center frequencies allocated inside four different sub-bands that have less than 50 kHz bandwidth and quality factors exceeding 8000. We see promise of standard, low-cost photolithography techniques being used to fabricate multiple SAW resonators with different center resonances all inside the 433.05 MHz–434.79 MHz ISM band and a mere 100 kHz spacing. We achieved that by leveraging the intrinsic process variation of photolithography and the impact of the metallization ratio and metal thickness in rendering distinct resonant frequencies.

Original languageEnglish
Article number4294
Pages (from-to)1-13
Number of pages13
JournalSensors (Switzerland)
Issue number15
Publication statusPublished - 31 Jul 2020

Keywords / Materials (for Non-textual outputs)

  • ISM band
  • Metal thickness
  • Metallization ratio
  • Process control
  • Resonator
  • Resonator arrays
  • Surface acoustic waves
  • WSN


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