Abstract: An antenna for a wide bandwidth electromagnetic field polarized in a predetermined direction at right angles to the field propagation direction includes plural metal elements that are not resonant in the bandwidth. The metal elements are excited to transduce an electric field in the polarization direction over the bandwidth range. The plural elements have an extent in the polarization direction no greater than an order of magnitude of the shortest wave length in the bandwidth. A structure between the element, which may be either a coil or parallel electrodes which derive a displacement current, transduces a magnetic field having lines of flux at right angles to the polarization and propagation directions. The electric and magnetic fields are excited by power from the same source with phases so that in an interaction region of the field between a pair of the metal elements there is E.times.H synchronism and a radiation Poynting vector having rotational E and H fields to transduce the electromagnetic field.

Abstract: In general a coaxial feeder connected directly into the center of a half-wave dipole antenna disturbs electrical balance and therefore reduces the effectiveness of the screen of the feeder. In the present invention a dipole with two quarter-wavelength elements symmetrically connected through respective identical capacitors to the screen of the feeder is fed through an inductor connected to the junction between one element and its capacitor. By having equal reactances, the capacitors balance the dipole to earth and by means of its phase delay the inductor restores a resistive impedance termination for the feeder.

Abstract: Multiband dipole antennas connected to a coaxial feeder are usually not balanced and are not operated at maximum efficiency. In the present invention pairs of capacitors are connected at the feed point of respective half-wave dipoles, associated with different frequency bands to reduce these deficiencies. A similar technique is useful for single band half-wave dipoles and allows unbalanced multiband ground plane antennas to be constructed.