Development of a 3D scanning system for magnetic near-field characterization

This paper presents a near-field scanning system with the design and calibration of two three dimensional (3D) magnetic field probes. They consist of three orthogonal loops, combined together, the first probe (P1) contains three conventional loops joined in a plastic cube, and the second one (P2) is a PCB probe printed on an FR4 substrate of 3.2 mm thickness. Probe P1 has a total dimension of 10x12x13 mm
³
whereas in probe P2 the dimensions are reduced to 9x9x3.2 mm
³
. The antenna factor of the designed probes was calculated using TEM cell for a frequency range from 10 MHz to 1 GHz. The probes were validated using a standard circuit. Then they are used to characterize the radiated magnetic field from an RFID reader antenna.