Standard Magnetic Field Radiated by Two Loop Antennas in a Coplane

A RF magnetic field generator consisting of two radiating loop antennas placed in a coplane is proposed, which has relatively uniform field distribution and permits easy alignment of the antennas. A standard field generator based on this idea, having flat frequency characteristics up to 30 MHz, has been designed and tested. It was confirmed that misalignment of the receiving antenna up to 2 cm, for a distance of 30 cm between the radiating loop and the test point, causes an error of only ±0.1 dB. In terms of frequency characteristics, the field strength at the test point was flat within ±0.15 dB from 1 to 30 MHz.