Diffraction on the axes of disks and apertures*

Abstract

For the first time we have measured |H/H0|2 in the near-field diffraction of the magnetic fields of microwaves on the axes of conducting disks and their complementary apertures in conducting screens. Our magnetic loop detectors contained Schottky diodes and miniature capacitors. We found that magnetic tape made for tape recorders does not (i) perturb the fields or (ii) behave as a single-wire transmission line to conduct the fields away from the probe. We used this iron oxide type of magnetic tape as leads from our probes to the electrometer. Employing our previous measurements of |E/E0|2 and using the Babinet principle in electromagnetic form, we plotted the complex spirals for the amplitudes and phases for the four cases of the diffracted electric and magnetic waves on the axes of circular disks and complementary circular apertures on the side of the screens opposite the source.