Patent ID: 8884834

Claim:
A broadband antenna system comprising: a broadband free-space antenna that is capable of radiation or reception of an electromagnetic wave over a bandwidth that extends from a low-frequency (f low ) to a high-frequency (f high ) and does not employ a ground plane to establish a resonant radiator structure; wherein the broadband free-space antenna has a radiative structure with a surface; and a high-impedance backing positioned adjacent to the surface of the radiative structure of the free-space antenna to allow the surface to be positioned: (a) adjacent to a conductive surface that would otherwise have a substantial adverse effect on the bandwidth of the free-space antenna and (b) within λ low /4 of such a conductive surface, where λ low is the wavelength of f low , the high-impedance backing also capable of accommodating a predetermined amount of power; wherein the high-impedance backing includes (a) an array of conductive pins, (b) a first dielectric located between the surface of the radiative structure and the array of conductive pins, and (c) a second dielectric located between at least one pair of pins in the conductive array of pins; wherein each pin in the array of conductive pins extends from a first terminal end to a second terminal end, the first terminal end separated from the surface of the radiative structure by a first distance, and the second terminal end separated from the surface of the radiative structure by a second distance that is greater than the first distance; wherein the broadband free-space antenna, in operation, produces an electromagnetic wave with an E-field that passes through the high impedance backing, the E-field at any location in the high impedance backing being represented by an E-field vector that specifies an E-field direction and a magnitude that decreases with increasing distance from the surface; wherein pins in the array of conductive pins each has a shape and position and is made of a material that: (a) presents a high reactive impedance and low ohmic loss to the broadband free-space antenna, (b) is substantially insusceptible to an E-field inducing a current within the pin, (c) is substantially non-resonant, and (d) can accommodate the predetermined amount of power.