Spherical Near-Field Thermal Drift Correction using a return to peak Technique

Authors: G. Bruce Melson, Doren W. Hess, John R. Jones

Publication: AMTA 1985

Copyright Owner: NSI-MI Technologies

Over the long periods of time needed to acquire spherical near-field data, thermal drift of the system can cause errors in the measurement. The effect of thermal-drift can be removed, if it is monitored during the scanning process. This is accomplished by periodically returning the probe to the near-field peak during acquisition. The same point is re-measured upon each return; and the variations in phase and amplitude are used to produce a correction factor which is applied to each point in the near-field data file. This paper describes the return-to-peak method and the correction algorithm. Experimental results will also be presented.