Antenna Diagnostics using Near Field Techniques
conference paper
The radiation characteristics of an antenna are fully determined by its aperture distribution. Measured Near Field data gives an impression but this is not good enough to detect small anomalies. For good antenna diagnostics, the field at the aperture plane is required. The Near Field Measurement Technique calculates the Far Field of the AUT is by determining the so called Plane Wave Spectrum (PWS) from the measured Near Field data. Once the PWS is known, the electric field at any location can be calculated. In fact, the Far Field is only a limiting case of the PWS. Using the PWS, the field at the aperture of the AUT can be calculated. This aperture image is much "sharper" than the measured Near Field. Even small anomalies, hardly visible in the measured Near Field data, appear quite clearly. To determine the excitation coefficients of array elements, the Far Field data has to be corrected for the element radiation pattern. Unfortunately, some steps in the processing confine the accuracy of these methods
TNO Identifier
94875
Publisher
ESA/ESTEC
Source title
Proceedings ESTEC/EMSL Workshop on Large Microwave Measurement Facilities, November 27/28 1995, ESTEC, Noordwijk, The Netherlands
Place of publication
Noordwijk
Pages
263-267