Date of Award

2011

Level of Access Assigned by Author

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical and Computer Engineering

Advisor

Mauricio Pereira da Cunha

Second Committee Member

Donald H. Hummels

Third Committee Member

David E. Kotecki

Abstract

A detailed analysis is presented for calculating the per-strip admittance of peri-odic electrode gratings on piezoelectric substrates. Based on this analysis, a new method is described for identifying substrate orientations along which low-attenuated, strongly-coupled high-velocity pseudo-surface acoustic waves (HVPSAWs) exist. An extensive search for HVPSAW orientations of lithium niobate (LNO) and lithium tantalate (LTO) is reported, and new HVPSAW orientations are identified. HVPSAW dispersion proper-ties for periodic gratings comprised for aluminum, gold, and platinum electrodes along various orientations of LTO are presented. Simulated and measured electrical responses of HVPSAW devices along these orientations are nearly identical. A detailed analy-sis of bulk acoustic waves (BAWs) radiated by interdigital transducers (IDTs) and the angular distribution of acoustic power is presented. The effect of mass loading by finite thickness electrodes on transducer efficiency is quantified. A rigorous analysis of the acoustic scattering properties of finite periodic gratings is detailed. Based on this anal-ysis, a new method for determining surface acoustic wave (SAW) network model (NM) parameters is presented. The resulting network model is applicable to arbitrary substrate orientations, including those which exhibit the natural single-phase unidirectional trans-ducer (NSPUDT) effect. Network model simulations and measured electrical responses of two-port SAW resonators devices along both symmetrical and NSPUDT orientations agree very well. An augmented network model for SAW structures is presented which incorporates radiation and scattering of bulk acoustic waves. This new model precisely mimics pseudo-SAW and HVPSAW behavior in periodic electrode structures.

Download

Share