Illustration of Rectenna

1964 Rectenna

The book of science

Tom Sharp

William C. Brown electromagnetism Illustration of Rectenna


William C. Brown invented the rectifying antenna as part of his design for wireless power transmission. He demonstrated a model helicopter containing a small rectenna and powered by microwaves.

Rectenna uses

A RFID tag is powered by radio waves gathered and rectified by its rectenna to transmit its data to an RFID reader. A satellite in constant sunlight may collect solar energy and send it as microwaves to large rectenna arrays on Earth. An optical rectenna may convert light waves directly into electricity, although challenges for its design and manufacture remain.


Nikola Tesla’s wireless power transmission used resonant induction, which he thought would let him transmit power to any point on Earth if he could make Earth’s potential resonate. Early attempts to invent radio transmission caused confusion between electromagnetic induction (which is used today only between nearby wire coils) and electromagnetic radiation (which can travel long distances). I wrack my brain for other forms of energy that we could harvest with rectennas. I’m wondering, “Virtual particles?” So many are whirring about from quark to quark!

William C. Brown’s design for a rectenna featured diode bridges producing a continuous pulsed direct current. The difficulty in producing optical rectennas is that even the fastest diodes today cannot handle the high frequencies of light waves.

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