Meaning
Configuration for antenna testing where a probe moves across a flat two dimensional surface to map the electromagnetic field. Automated planar scanning geometry is most effective for highly directional antennas with narrow beamwidths.
Spatial Limitation
Because the probe only travels on a single plane, planar scanning geometry is unable to characterize the back lobes or side lobes that fall outside the forward facing hemisphere. Test technicians often use this method for high gain apertures where the radiation is concentrated in a tight main beam, allowing for faster data collection compared to spherical or cylindrical methods. The distance between the antenna and the scan plane is carefully chosen to avoid multiple reflections that could contaminate the measurement.
Mechanical Precision
High speed linear actuators maintain the alignment required for planar scanning geometry by moving the probe along a precise grid. Any deviation from the intended path introduces phase errors that distort the final radiation pattern.
Data Processing
Engineers apply a windowing function to the data collected via planar scanning geometry to minimize the artifacts caused by the edges of the scan area. This technique ensures that the resulting far field calculation represents the true performance of the antenna.
