FM-CW Measuring Technique for Testing Wideband Anechoic Chambers

The Voltage Standing Wave Ratio and the Antenna Pattern Comparison methods are widely used for the determination of the reflectivity in anechoic chambers. In this paper a reflectivity measuring technique is described based on a transmitted signal with a linear frequency modulation over a large bandwidth. The main advantages of the technique described are the possibility to obtain the spatial distribution of the reflectivities inside the chamber, the quasi-real-time signal processing using existing Fast Fourier Techniques and the visual presentation on a quick-look monitor.