A multipurpose EM field measurement and antenna calibration facility

Details of a multipurpose electromagnetic (EM) field measurement facility are described. A three-dimensional robotic probe positioner, modern computer-based instrumentation and specially developed hardware and software for data acquisition, and analysis and graphical presentation permit a large number of measurements in a relatively short time. Flexible and modular design of system components, subsystems, instrumentation, and software renders the facility useful in many diverse applications. Some of the measurement programs undertaken include: Measurement of antenna input impedance as a function of frequency and height. Three-dimensional distribution of E-field due to a variety of antennas in the presence of associated environment such as the walls of an imperfect absorber lined chamber and a reflecting ground plane. Calibration of antennas to be used as probes for EM field measurements. Measurement of scattering properties of absorbing material. Measurement of EM emission characteristics of electronic equipment.