Multiple Probe Nearfield Scanning for EMC-Investigations

Antennas such as log-periodic arrays are often used to quantify the emission of electromagnetic radiation from a test object. The calibration of such relatively large antennas is a challenging task with conventional farfield measuring sites, while nearfield scanning offer an advantageous alternative. From basic electromagnetic theory it is well-known that correct farfield data from a nearfield to farfield transformation can only be obtained if the nearfield is measured on a closed surface around the antenna under test. The consequence of sequentially scanning on a closed envelope is that measurement time becomes considerable, which cannot be accepted if these involve test persons. To overcome these drawbacks, a new multiple probe scanning technique is proposed.