"Compact ranges - Past, present, and future"

The compact range has been used for electromagnetic measurements since the early 1950´s. Although the early attempts with such systems had some successes, they were not generally used until the middle of the 1970´s. This recent interest was sparked by a commercially available system developed by Scientific-Atlanta. This system was specifically designed and tested for antenna applications, even though the earlier tests were made in terms of scattering measurements. Based on the recent interest in radar cross-section, the compact range has been re-examined in terms of its capabilities for measuring the scattering properties of large structures. The Ohio State University has been one of the pioneers in developing the proper use. capabilities; and modifications necessary to make the compact range one of the most accurate electromagnetic pattern measurement systems available. As a result, new systems have been designed using various electromagnetic analyses to guide this research effort. These changes include the reflector, feeds, target mount, instrumentation, absorber, target handling techniques, data processing, calibration methods, calibration targets, etc. In most cases, the theoretical solutions have been verified by experimental results, and in some cases, the new designs have been incorporated in Commericial products. The presentation will attempt to cover the latest and more interesting aspects of this challenging new area.