A simple transducer equivalent circuit parameter extraction technique

Abstract

This paper presents a simple technique for extracting the fundamental SAW transducer equivalent circuit parameters from measurements easily performed on a network analyzer. This technique allows for the separation and unambiguous determination of basic equivalent circuit parameters such as parasitic (thin film) resistance, transducer capacitance, acoustic susceptance, and Hilbert Transform conductance. It is applicable to any transducer geometry, but is particularly useful in model development for unconventional transducer structures, such as narrow gap or multilevel devices. In such cases, quantities such as transducer capacitance and effective coupling may not be easily calculated from previously known relationships. The basic theory for parameter extraction is presented, along with a comparison of experimental data and modeled device performance calculated using the extracted values