ليث كاظم تركي ابو هدمه

The accuracy of navigation systems depends on the direction finding of passive objects or beacons and is based to a decisive extent on the antenna characteristics. Measuring antenna radiation pattern (ARP) is an important step in both the design and verification phases. Nevertheless, many universities and small technology companies do not have the proper infrastructure to run this type of test. In this paper, we analyze the possibility of retrieving ARP from the measurements in non- ideal test conditions, which are mainly due to the short distance to the irradiator and the moderate quality of the absorbent coating on the walls of a compact chamber. The basic idea is to represent the total field irradiating the tested antenna by a converging cluster of plane waves. To do this, a probe antenna must first measure the total field on the surface surrounding the antenna under test. The results of the numerical simulation confirm the robustness of the proposed algorithm for retrieving ARP from the data of real measurements.

Large collimator setups are often in use for antenna radiation pattern measurements. Their quiet zone size limiting the allowable dimensions of the antenna under test, as a rule, do not exceed a half of the collimator's profile. Retrieving ARP from measurements in a non-ideal environment can be a means to expand the working area. The subject of the article is such a technique based on of the representation of a real field by a converging cluster of plane waves. It turned out that at the stage of studying the field of the collimator, despite the requirements of the uniqueness theorem, measurements may be carry out on a certain limited area of the boundary surface. Acceptable results are obtained when the working area is up to 90% of the collimator cross section.