Polarization current antennas include an arc-shaped dielectric radiator, electrodes, and a feed network. The electrodes and feed network are configured to generate an electric field within the dielectric radiator. The electrodes are positioned on the top and bottom of the dielectric radiator and the electromagnetic radiation is emitted through the outer surface thereof. Phase differences between excitation signals supplied to the electrodes may be selected so that a speed of a volume polarization distribution current pattern that is generated in the dielectric radiator will be substantially equal to the speed of light within the dielectric radiator. The antenna emits both conventional spherically decaying electromagnetic radiation and as non-spherically decaying electromagnetic radiation that decays as a function of distance d at a rate that is less than 1/d.sup.2. The non-spherically decaying radiation includes a highly focused beam that has an angular beamwidth that narrows as the distance d increases.

This application provides a multi-band shared-aperture antenna. The multi-band shared-aperture antenna includes a first antenna array, a second antenna array, and a reflection panel, where the first antenna array includes four first dielectric plates perpendicular, two adjacent first dielectric plates are perpendicular to each other, the first antenna array includes four hollowed butterfly dipole units, the dipole unit includes two radiation arms, the two radiation arms are respectively printed on two adjacent first dielectric plates, the radiation arm includes a first part and a second part, a first feeding stub is disposed on the first dielectric plate, the second part has a specified width in a direction perpendicular to the reflection panel, the second antenna array includes a plurality of second dielectric plates, four ring-shaped coils are disposed on any one of the second dielectric plates, and the ring-shaped coil is connected to a second feeding stub.