Paraboloidal reflectors with axial excitation

The reflectors are deep paraboloids having axially oriented dipoles at the foci. Odd-function aperture distributions and radiation patterns are derived by approximate methods and are compared with an experimental polar diagram. In spite of a null along the axis, strong coupling at short range is observed between two aligned aerials. This is associated with a coupling diagram of abnormal directivity, which may be explained by a principle of field-fitting between the incident field and the normal aperture distribution. A reduction of Maxwell´s equations in paraboloidal co-ordinates to Bessel´s equation is appended.