so I am hatching an idea for a system of equipment which requires a focussed wavelength which will not greatly widen over distances of less than a mile. Also the waveform needs to be sensible by receiver antenna or something of a similar nature. It is necessary that the waveform be able to penetrate at least an average layer of clothing before contacting the receiver and ideally be able to pass through light structural materials (think drywall). The end target of this waveform will be human tissue so it has to be biologically inert or have at most some negligible effects over time and repeated exposures. I'm not sure if a laser/maser or related phenomenon is the answer but to my knowledge it is the closest existing solution to my question. If anyone has any other ideas I would greatly appreciate suggestions.