The RF transformer application for ultrasound excitation: the initial study

Abstract

Practical aspects of RF transformers design and application in ultrasonic system excitation channel are analysed. Design steps are discussed for those willing to design their own transformer design for excitation channel. Investigation has been carried out on what generator parameters can be obtained if instead of purely active output stage impedance matching RF transformer is used. It is assumed that low output impedance active stage is coupled into relatively high impedance ultrasonic transducer. Air coupled ultrasonic transducer has been used as reference for the calculations. Several materials are considered for RF transformer core and possible candidates and their properties for 10kHz to 10MHz frequency range are listed. The algorithm for performance investigation using only manufacturer parameters and the Matlab modelling has been presented. The experimental study has confirmed RF transformer suitability as voltage step-up component for ultrasonic transducer excitation. The 0.1…10MHz passband is achieved. The results obtained at different transmitted power levels (from 50mW to 0.5W) indicate there is only slight reduction in the bandwidth. The presented configuration can be used for ultrasonic transducer excitation using arbitrary waveform generator.