Performance measurement of frequency selective reflector using planar near-field techniques

A frequency selective reflector (FSR) composed of periodically arranged resonant elements is well known as a filter which separates two or more waves with different frequency bands spatially, and is used in multiband reflector antennas. The simple scheme used to measure the propagation loss due to the inserted FSR in the transmission path consisting of two opposite horns is a reliable method of estimating the characteristics of the FSR. However, it is difficult-to evaluate the characteristics of the small parts of the FSR. We investigate a measurement scheme for the reflection and transmission coefficient distribution on an FSR using planar near-field techniques, which has been applied in order to estimate the antenna's characteristics, such as far-field patterns, gain; and the reflector surface accuracy.