Definitions Relating to Conversion Losses in Piezoelectric Transducers

As there seems to be no unanimity on conversion loss definitions and their interrelations with the equivalent cir- cuit formulations describing piezoelectric transducers and de- vices, this paper gives a tutorial review of elementary relations between various loss definitions. A proper separation of losses arising in matching to the transducer and conversion losses within the transducer is of practical importance for the design of devices, as the former affects predominantly the passband shape and achievable gain-bandwidth product, and the latter is of relevance for thermal problems.