High Accuracy Spherical Near-Field Measurements On a Stationary Antenna
Authors: Greg Hindman, Hulean Tyler
Publication: AMTA 2010
Copyright Owner: NSI-MI Technologies
Most conventional spherical near-field scanning systems require the antenna under test to rotate in one or two axes. This paper will describe a novel rolling arch near-field scanner that transports a microwave probe over a hyper-hemispherical surface in front of the antenna. This unique scanning system allows the antenna to remain stationary and is very useful for cases where motion of the antenna is undesirable, due to its sensitivity to gravitational forces, need for convenient access, or special control lines or cooling equipment. This allows testing of stationary antennas over wide angles with accuracies and speeds that historically were only available from planar near-field systems.
The probe is precisely positioned in space by a high precision structure augmented by dynamic motion compensation. The scanner can complete a hyperhemispherical multi-beam, multi-frequency antenna measurement set of up to eight feet in diameter in less than one hour.
The design challenges and chosen techniques for addressing these challenges will be reviewed and summarized in the paper.