Nearfield Systems Inc. - Accessories

Spherical Scanners

Phi over Theta

Theta over Phi

Stationary AUT


AUT Motion

Phi over Theta Phi None

Probe Motion

None Theta Phi & Theta


Lowest ceiling clearance AUT moves in only 1 axis No AUT motion

Theta axis




Phi axis

Horizontal Vertical Horizontal

Typical large SNF scanner M/N

NSI-700S-75 NSI-700S-150 NSI-700S-300


NSI offers a large variety of Spherical Nearfield Antenna Measurement Systems of various sizes and configurations. The most common is the “Phi over Theta” systems where the AUT is mounted on the Phi positioner, which in turn is mounted on an L-bracket, mounted on a Theta positioner. In this case, the AUT is required to move for both the Theta and Phi motions, and the probe remains fixed. The second configuration we support is the “Theta over Phi” configuration. In this configuration, the probe is moved in an arc above the antenna to provide the Theta motion, and the AUT is mounted on a positioner and rotated to provide the Phi motion. A third configuration we support is the “Stationary AUT” configuration, where the probe is moved to provide both the Theta and Phi motions, and the AUT remains fixed. This is ideal when rotating the AUT is difficult or impossible.