On the Wave Propagation Through Apertures

A multi -channel phased array is used to synthesize signals of varying frequencies through apertures in EM shielded structures. Bipolar impulses with a GHz frequency spectrum are emitted from multiple antennas and used as basis functions to pass through the aperture and undergo constructive and destructive interference at a specific point in space. Experiments based on a small antenna array demonstrate that this technique enables synthesizing a below GHz signal (~ 400 to 800 MHz) in a shielded volume with an open aperture size that would heavily attenuate a direct sub-GHz electromagnetic wave. While the experimental results demonstrate that this technique is effective at UHF frequencies, it is certainly not limited to this frequency band.