Applicability of Radiowave Anechoic Chambers for Acoustic Free-Field Measurements on the Example of the Chamber at ITMO University

TL;DR

This study investigates whether a radiowave anechoic chamber can be used for acoustic measurements, finding it feasible within certain frequency ranges and measurement conditions, thus potentially reducing resource requirements for acoustic testing.

Contribution

The paper evaluates the acoustic properties of a radiowave anechoic chamber, demonstrating its potential dual use for electromagnetic and acoustic free-field measurements.

Findings

Chamber can be used for acoustic measurements within specific frequency ranges.

Acoustic properties depend on measurement direction and distance.

Chamber meets ISO 3745:2012 standards under certain conditions.

Abstract

Acoustic anechoic chambers allow free-field measurements required for the verification of effects under investigation and for the characterization of developing devices. However, the construction of an anechoic chamber is a labor-intensive process that requires a lot of resources, which is why these facilities are rather rare. An analogous statement can be made about radiowave chambers. At the same time, it is known that materials for radiowave absorption might absorb acoustic waves as well, and it can be expected that some chambers can be utilized for both electromagnetic and acoustic free-field measurements. This work examines the feasibility of the radiowave anechoic chamber of ITMO University (Saint-Petersburg, Russia) for acoustic measurements. The acoustic properties of the chamber coatings are estimated via measurements and numerical calculations. Characterization of sound pressure level, background noise level, and reverberation time is performed in accordance with the ISO 3745:2012 standard. The key conclusion is that the chamber can be considered as an acoustic anechoic chamber, but only for specific frequency ranges and distances from the source, which depend on the measurement directions.