Evaluation of the Intermodulation Product Performance of Reflector Antennas and Related Structures by Microwave Imaging

Abstract

Reports upon further developments that have been made in the adaptation of the microwave imaging technique to locate sources of intermodulation produce (IMP) generation upon microwave reflectors and related structures. The objective of this research work is two fold. Firstly it is hoped to provide a new means of evaluating the IMP performance of reflector antennas and, by locating the sources of IMP present, to show how it might be possible to improve the IMP performance by reducing or eliminating these sources. Secondly, it is hoped that by using the imaging process it may be possible to study to the causes and effects of IMP generation upon reflectors and similar such structures. For conventional microwave imaging and antenna metrology, the target under investigation is illuminated at a single frequency and acts as a passive scatterer to this illumination. In the present case however, the object is illuminated by high power source feeds at least two different frequencies, inducing an active response in the form of IMP generation. All measurements and data evaluation are then performed at the frequency of the chosen IMP signal.<>