Fractal Antenna said the device is a variation of the invisibility cloak technology invented by its Chief Executive Officer Nathan Cohen.
"A deflector shield uses cloak technology not to hide an object but to pass radiation around it," Cohen said. "There is no attempt to 'image.' Not only is the power deflected safely to the other side but there is virtually no change to the object caused by the radiation pressure, unlike a mirror or an absorber.
"There is no 'bounce back'. This is truly a new and novel technology."
The deflector shield used in the test was constructed as a vest and worn by one of the firm's team. The vest comprised an inner copper layer and fractal-shaped meta-materials conforming around it.
In the test, 90 percent of the electromagnetic power from microwaves aimed at the subject passed around him.
Cohen is to demonstrate the technology Friday at the Radio Club of America in New York, the company said.