Advantages and Disadvantages of Various Hemispherical Scanning Techniques
Authors: Eric Kim, Anil Tellakula
When performing far-field or near-field measurements on large antennas, it is often necessary to consider the advantages and disadvantages of various mechanical positioning configurations for achieving the required hemispherical scan coverage. Measurement systems employing a single-arm gantry, a dual-arm gantry, a fixed arch moving probe, and a fixed arch multi-probe have been paired with either an azimuth positioner or a vehicle turntable in order to provide hemispherical scanning of the article being tested.
This paper will highlight the key characteristics of various scanning methods and provide comparisons among the different techniques. Positioning and system accuracy, speed, stowing capability, calibration, frequency range, upgradability, relative cost and other key aspects of the various techniques will be discussed in detail to help the end user during the system design and selection process. In addition, the paper will highlight novel hemispherical and truncated spherical scanning approaches.
In many applications, the success of meeting the measurement requirements often centers on the judicious selection of the positioning subsystem. This paper will provide guidance toward making the proper selection of the scanning concept as well as of the positioning system.