Fast Multi-Probe Planar Near Field Measurements With Full Probe Compensation

The measurement needs for space and military industries are constantly evolving, and more often require the characterization of electrically large and multi-port antennas. Planar Near-Field systems (PNF) offer advantages over other test solutions, at the cost of longer acquisition time. The use of multi-probe technology to partially replace slow mechanical scanning is a proven solution to reduce the measurement time. In PNF systems, the effect of the probe must be compensated to achieve sufficient measurement accuracy. The standard calibration used in multi-probe systems provides equalized on-axis probe responses in amplitude/phase and polarization. The probe pattern is approximated from a separate calibration of the probe array elements before installation. Unfortunately, this approach can be time consuming and expensive. A novel technique to determine the multi-probe pattern for accurate PNF compensation is presented. The calibration process is explained and validated by experiment using measurements conducted in a recently installed planar multi-probe system.