Abstract: A coaxial helical antenna for transmitting or receiving information through electromagnetic waves includes a first helical antenna comprising a first helix comprising a first diameter and a center cavity; a second helical antenna comprising a second helix comprising a second diameter, wherein the second diameter is smaller than the first diameter, and wherein the second helical antenna is seated within the center cavity of the first helical antenna; a shaped ground plate coupled to the first helical antenna and the second helical antenna; and two microstrip impedance transformers coupled to the first helical antenna, the second helical antenna, and the shaped ground plate.

Abstract: An electromagnetic structure for reflecting electromagnetic waves comprising a first surface having spaced patches of conductive material thereon; a second surface separated from the first surface, having spaced patches of conductive material, the first and second surfaces having high impedance and thrilling substantially optimal magnetic conductors; adapted to be used in conjunction with an associated antenna that radiates electromagnetic radiation originating therefrom, the radiation is reflected by the electromagnetic structure such that the phase of the electromagnetic waves reflected from first and second surfaces results in the constructive addition of the originating and reflected waves.

Abstract: A coaxial helical antenna for transmitting or receiving information through electromagnetic waves includes a first helical antenna comprising a first helix comprising a first diameter and a center cavity; a second helical antenna comprising a second helix comprising a second diameter, wherein the second diameter is smaller than the first diameter, and wherein the second helical antenna is seated within the center cavity of the first helical antenna; a shaped ground plate coupled to the first helical antenna and the second helical antenna; and two microstrip impedance transformers coupled to the first helical antenna, the second helical antenna, and the shaped ground plate.