Estimating far-field errors due to mechanical errors in spherical near-field scanning

When the mechanical requirements are established for a spherical near-field scanner, it is desirable to estimate what effects the expected mechanical errors will have on the determination of the far field of potential antennas that will be measured on the proposed range. The National Institute of Standards and Technology (NIST) has investigated the effects of mechanical errors for a proposed outdoor spherical near-field range to be located at Ft. Huachuca, AZ. This investigation was performed by use of theoretical far-field patterns and introducing position errors into simulated spherical near-field measurements. Far-field patterns were then calculated with and without probe-position correction to determine the effects of mechanical position errors. This paper reports the results of these investigations.