The Design of an Automated, High-Accuracy Antenna Test Facility

This paper presents the step-by-step application of proven far-field range and instrumentation design techniques to a specific antenna measurement problem, describes the resulting facility design, and presents the predicted measurement uncertainty. Fundamental electromagnetic design criteria for an outdoor, far-field facility establish minimum dimensional requirements for the range design and limiting values of source-antenna directivity. Electromagnetic compatibility of the facility is assured by frequency coordination with existing and planned services in the area surrounding the available site. Additional design constraints for this facility included restricted measurement time, reduction of spurious test enclosure effects, limited available terrain, and required data quality. In this case, the required range length is in excess of 6500 ft, and paraboloidal source antenna diameters up to 23 ft are required. The frequency coordination problem was solved by exploiting the natural terrain features and configuring the measurement system as "test-on-transmit." Signal and reference paths share the same range cable. The quantity of data that must be handled in the available measurement interval required the use of a computer-based measurement system.