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Small Antenna Handbook by Robert E. Collin, Robert C. Hansen

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Chapter 5

Pathological Antennas

Claims on these antennas typically have performance characteristics that violate the physical laws we work under.

5.1 Crossed-Field Antenna

The crossed-field antenna (CFA) was conceived by Hately and Kabbary in the late 1980s. It was based on several “new” principles: that img and img fields could be created independently, that Maxwell's displacement current produces magnetic fields, and that the near-fields could be avoided. The basic geometry is shown in Figure 5.1: Two horizontal circular metallic disks form a capacitor that is excited by the transmitter, but it is alleged that the displacement current between the plates produces an azimuthal magnetic field. Two hollow metallic circular cylinders are stacked vertically, and above the horizontal plates. The transmitter also excites the cylinders, but 90° out of phase with the plate excitation. An electric field is produced by the cylinders as sketched. Because of the Poynting vector, the img and E fields radiate a wave into space. Several of these CFAs have been built, at MF. Later versions have incorporated a large flare structure into the upper cylinder, presumably to increase the electric field in Figure ...

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