COMPARATIVE PERFORMANCE OF PIEZOCERAMIC AND CRYSTAL SAW FILTERS

Bulk elastic, piezoelectric, and dielectric constants of four lead zir conate titanate piezoceramics, Pz24, Pz26, Pz27, Pz28, and a modified lead titanate, PTS, are measured and used to theoretically compute the effective permittivity curve of each material from which the surface acoustic wave (SAW) properties are deduced. In parallel, experimental measurements of the SAW properties are carried out by using a curve fi tting algorithm on the real and imaginary parts of the electrical inpu t impedance of an unapodised single electrode SAW transducer. The SAW propagation losses are also measured using a SAW delay line. For these ceramics, the effects of a hot isostatic pressing (HIP) post sinterin g process on the performances of the device are also studied. All thes e results are discussed and show that ceramic materials, particularly PTS, have potential for SAW applications.