On ferrite loop antenna measurements

A general discussion relating to the application of small loop antennas with air and ferrite cores is given. A general procedure for simplified testing of ferrite-loaded magnetic-type small antennas is outlined in which radio-frequency radiation performance is expressed in terms of quantities easily measured at audio frequencies. Only a single measurement is needed to characterize the elementary-dipole-type ferrite-loaded antenna. Finally, a number of measurement results are given which apply to the usual rod-type ferrite-loaded loop antenna: measurement parameters cover a broad range of core lengts and diameters. It is found that typical ferrite-loaded loops have little electrical advantage over air loops although the packaging advantage of ferrite loops may be significant.