An Aluminum Scandium Nitride (Al0.64Sc0.36N) Two-Dimensional-Resonant-Rods Delay Line with 7.5% Bandwidth and 1.8 dB Loss

Abstract

We report on the performance of the first Two-Dimensional-Resonant-Rods (2DRR) acoustic delay line (ADL) for operation in the Radio-Frequency (RF) range. Contrary to any other ADLs reported to date, which are based on the piezoelectric excitation of Surface Acoustic Waves (SAW) or Lamb Waves (LW), the ADL reported here relies on the lithographically defined artificial dispersive characteristics of acoustic metamaterials formed by forests of locally resonant rods as well as on the superior piezoelectric coefficients of highly-doped Aluminum Scandium Nitride (Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.64</inf> Sc <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.36</inf> N) films. The 2DRR-based ADL discussed in this work operates at 133 MHz and shows a record-high 5 dB fractional bandwidth of 7.5% as well as an insertion-loss of 1.8 dB.