Crossed field antenna
Cross -Field Antenna (short CFA), also EH antenna, is the name for a type of antenna for long wave, medium wave and short wave in which the electric (E) and magnetic (H ) field component of generated electromagnetic wave, each in different components of the antenna are generated.
In principle, the CFA is a form of Tesla transformer dar. practical as well as mathematically it can be shown that low wastage occur between similarly structured resonance structures, which makes them interesting for a wireless power transfer to load as batteries contact in wireless devices.
Optimal emission is only reached when the E-field and H-field phase-shifted by 90 ° to each other and perpendicular to each other and perpendicular to the direction of radiation produced (in other words, effective only in the immediate near field).
The design goal of this antenna was clearly missed. This was to achieve the same efficiency of a conventional transmit antenna ( for example, even radiant transmission tower or conventional dipole ) at much lower height. Compared to antennas with tuned lengths, the CFA has indeed potentially higher bandwidth; This does however present excessive antenna losses.
Practical experiments confirm that the cross -field antenna must be carefully matched and that their efficiency is significantly lower than that of the conventional dipole or loop antenna.
Other studies reportedly show at a CFA for 20 m wavelength, a against a stationary horizontal bundling Viertelwellendipol better or less radiating up and down and in consequence a greater range.