Design, Alignment, and Calibration Requirements for a Sub-Millimeter Wave Frequency Tiltable Lightweight Scanner
Author: Peter W. Bond, P.E., G. A. Ediss
This paper discusses design aspects related to a tiltable lightweight near-field scanning system for use at submillimeter frequencies. It addresses design issues as they relate to accuracy and scanner distortions from multiple causes. Calibration methods to measure and correct for anticipated and unanticipated errors are briefly addressed. Actual test results are presented.
The tiltable scanner being discussed was designed for the Atacama Large Millimeter/submillimeter Array (ALMA)  and is being used by the National Radio Astronomy Observatory (NRAO) . It has many other applications by virtue of its light weight (approx. 120 lbs) and ability to be oriented at different angles. These include flightline testing and other in-situ antenna test applications.