An antenna for receiving electromagnetic energy with multiple grid arrays includes first and second grid patterns of diodes each acting as a half-wave rectifying element when illuminated by the electromagnetic energy whereby the electromagnetic energy is efficiently converted into electrical current at an output even when the electromagnetic energy is randomly polarized. The multiple grid arrays are spaced from one another and can also be offset from one another. In accordance with an aspect of the invention, the first and second grid patterns of diodes have varying diode densities.