A Method for Measuring Reflection Characteristics of Building Materials for TV Broadcasting Wave Using a Small Sample

Abstract

This paper presents a new method for measuring reflection characteristics of building materials for TV broadcasting wave using a small sample of which dimensions are about one wavelength. The effect of incoming wave is cancelled out by using a hybrid junction combined with two antennas. Then the true reflection from the sample is extracted from measured data after removing the effects of multi-path reflections by means of a linear displacement of the sample. Both normal and oblique incidence of waves can be handled.
The principle and the subsequent error analysis are confirmed first by an experiment at 5 GHz using samples which are larger than and comparable with a wavelength. Then, reflection characteristics of a few samples are measured at 200 MHz, utilizing a TV broadcasting wave. A decay of reflection due to curing of concrete is detected.