Method for the Measurement of Scattering Coefficients Using a Metal-Plate Reflector in the Microwave Region

A new method for measuring the scattering coefficient using a metal-plate reflector was developed in order to provide a non-destructive way for the assessment of microwave materials in free space. By displacing the position of the metal-plate reflector on the specimen to be tested, the incident wave and the scattered wave from the measured area were determined without the influence of extraneous waves such as the direct coupling between transmitting and receiving antennas and scattered waves from background objects. Because the behavior of a metal-plate reflector is similar to that of an optical shutter in optics, our new scattering measurement system enables us to measure both backwardand forward-scattering coefficients of small regions of the specimen for various types of materials in a non-destructive manner. Our study examined the metal-plate size dependence of the complex reflection and transmission coefficients of some dielectric sheet samples. The measured data indicated that the reflection and transmission coefficients of a Bakelite flat plate and Styrofoam sheet were constant for various sizes of metal plates at the X-band. key words: scattering coefficient, reflection coefficient, transmission coefficient, non-destructive measurement