Development and Basic Calibration of an Acoustic Vector Network Analyser

Marcus Macdonell and Jonathan Scott

This project aims to develop a method that drastically improves measurement of the acoustic properties of objects. Previously research at the University of Waikato has made progress with acoustic technologies as a precursor to a dual port vector network analyser. These technologies have been furthered to this end by 3D printing a modified coupler that now includes a flange with alignment pins, and a groove to house an O-ring as well as a number of other ``custom'' components for the coupler assembly. This assembly has been interfaced successfully with a VNA and collected data, this process is not straightforward and requires carefully thought-out adjustment to produce sensible data. Complicating this process is the vast difference in propagation speeds for acoustic and electromagnetic signals. The swept measurements performed show promising results that further prove the hardware and indicate that particular calibration terms namely those for isolation that are normally ignored in the electromagnetic domain are potentially crucial in the acoustic domain.