High-Speed, Hardware-in-the-Loop Phased Array Calibration with a Compact Antenna Test Range

Phased array beamformer channel calibration plays an essential role in optimizing the array gain and beam-steering accuracy, which results in higher signal-to-noise ratio and better link performance. However, the planar near field probe scanning techniques which have frequently been applied to this calibration process are time consuming, primarily due to the requirement for a sequential probe positioning over each radiating array element. An alternative technique for a phased array beamformer channel calibration, based on per-element indirect far field measurements in a compact antenna test range, is presented. The deployment of a stationary feed antenna, combined with hardware-in-the-loop control of the beamformer attenuation and phase states, results in significantly faster calibration. Additionally, measurement errors resulting from residual radiation from array elements not under test are minimized with the aid of leakage supression measures.