Wikipedia
A rectenna is a rectifying antenna—a special type of antenna that is used to convert electromagnetic energy into direct current (DC) electricity. They are used in wireless power transmission systems that transmit power by radio waves. A simple rectenna element consists of a dipole antenna with an RF diode connected across the dipole elements. The diode rectifies the AC current induced in the antenna by the microwaves, to produce DC power, which powers a load connected across the diode. Schottky diodes are usually used because they have the lowest voltage drop and highest speed and therefore have the lowest power losses due to conduction and switching. Large rectennas consist of an array of many such dipole elements.
The invention of the rectenna in the 1960s made long distance wireless power transmission feasible. The rectenna was invented in 1964 and patented in 1969 by US electrical engineer William C. Brown, who demonstrated it with a model helicopter powered by microwaves transmitted from the ground, received by an attached rectenna. Since the 1970s, one of the major motivations for rectenna research has been to develop a receiving antenna for proposed solar power satellites, which would harvest energy from sunlight in space with solar cells and beam it down to Earth as microwaves to huge rectenna arrays. A proposed military application is to power drone reconnaissance aircraft with microwaves beamed from the ground, allowing them to stay aloft for long periods. In recent years, interest has turned to using rectennas as power sources for small wireless microelectronic devices. The largest current use of rectennas is in RFID tags, proximity cards and contactless smart cards, which contain an integrated circuit ( IC) which is powered by a small rectenna element. When the device is brought near an electronic reader unit, radio waves from the reader are received by the rectenna, powering up the IC, which transmits its data back to the reader.
Usage examples of "rectenna".
We require that triaxial cable with local rectenna lead-ins be laid through all living areas.
Corellian section of Nar Shaddaa, Han and Chewie had installed a military-grade rectenna, a ventral quad laser cannon, and concussion missile launchers between the mandibles.
The new grain elevator for the docks had been completed since he had sailed away, and up on the hill the two microwave rectennae loomed behind the new geothermal power plant, the second antenna already half covered with its wire net.
Seriously, the beam density is only twenty-three milliwatts per square centimeter at the center of the rectenna farm.