Radio frequency energy is the energy transmitted by sources that can generate electromagnetic fields like TV signals, radio signal, wireless networks and cell phone towers, by using specially designed circuits connected to a an antenna this electromagnetic energy can be harvested and converted into a usable DC voltage. One of the applications of this technology is in radio frequency identification tags in which harvesting device can receives an RF signal from a sensing device; this RF signal can supply enough power to let the RFID tag to send radio frequency back including identification information to any item of interest. The circuits designed for such applications can made relatively small and can convert the ambient electromagnetic waves to a usable DC voltage at distances up to 100 meters from the source of the RF signal. Depending on the environment and the power of RF signal available the power conversion circuit would be connected to a capacitor which can provide a constant required voltage to the device in question when there is not enough supply of energy available also this RF power can be used to charge batteries. Another appealing feature of harvesting available RF energy is that it can be used as a supplement to the conventional energy harvesting methods. These energy harvesting techniques can be used to charge batteries at night when solar energy is not available and they could be used as backup system if the main supply of energy fails and keep the device working or send an alarm. This technology can extend the battery lifetime and that can be done by offsetting the sleep current required by low power microcontroller.
Antenna Design and Power Management for Wireless Energy Harvesting Application:
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...ation of rectenna array configurations for enhanced RF Power harvesting”, Loughborough Antennas & Propagation Conference, 2009.
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Wireless begins with a brief discussion of the 1995 centennial of the invention of radio by Marconi and a rebuttal by the British historians who oppose this claim. Using underused or previously overlooked or perhaps ignored resources the author disproves the claims against the originality and ingenuity of Marconi's 1897 patent on wireless telegraphy. While credit is given to several British scientists and engineers and their scientific discoveries and inventions, it was Marconi, a practitioner, who made the first significant breakthrough in practical wireless telegraphy when he "connected one end of the plate of the receiver, and one end of the transmitter, to the earth" (p. 20). Marconi transformed these scientific effects into wireless technologies and then exploited them for commercial purposes. The focus of British scientists and engineers on optical analogies, scientific experimentation and demonstration, and the fear of British national interests becoming monopolized (particularly by a foreigner) are the primary reasons for the dispute surrounding Marconi's patent. (By 1897 it was clear how wireless telegraphy would impact military interests.) The author shows in great detail how British scientists and engineers, namely physicist Oliver Lodge, J. J. Thomson, Minchin, Rollo Appleyard, and Campbell Swinton, deliberately constructed false scientific and social claims to discredit the originality of Marconi's patent.
Radio systems must have transmitter to modulate some property of the energy produced to impress a signal on it. To using amplitude modulation or angle modulation ,which can be frequency modulation or phase modulation. Radio systems have antenna to convert
"The Future of the Wireless Art," Wireless Telegraphy and Telephony, 1908, pg. 67–71, Nikola Tesla
L. Ophir "802.11 Over Coax - A Hybrid Coax - Wireless Home Network Using 802.11Technology", Consumer Communications and Networking Conference, pp.13 -18
Radio Detection And Ranging (RADAR) “is a method of using radio waves to detect the existence of an object and then to find its position in relation to a known point, usually the site of the radar installation.” Radar technology can be used to detect the position, speed, and direction of the moving or stationary objects (“Pulse-modulated”). Radars, often used for “electromagnetic surveillance,” has various hardware and software parts that work together to produce an effective reading of the position and motion of the objects. The transmitter of the radar is used to initiate the process by amplifying the pulse signals. It has three parts: “a high powered amplifier (HPA) with a high-stability electron gun, waveform generator and timing, and an antenna” (Kolawole, 37). “The low energy signal, collected by the antenna, is brought through the circulator and the transmit...
All The Light We Cannot See: Radio A spark ignites life within the embodiment of a metal case. As Werner, one of the main characters in the novel “All The Light We Cannot See”, mends the copper conduits a spark pulses through wire, circuitry and antenna. The sparks bend into vitality, crafted outside it’s engineered purpose. The vitality manipulates electromagnetic waves producing sound and thought.
To achieve the best possible way to heat up your meals, the microwave does not use solid state devices. Instead, electron beams from tubes under the combined effect of the electric and magnetic fields that are made to curve and follow trajectories. Magnetrons are also mostly used in microwave ovens and it has changed everything. In 1921 it was first discovered and put into use and as the years continue...
The radio works because of sound waves being transmitted from one receptor to the next. Electrons moving through a wire create a magnetic field and when a second wire is placed next to the first the electrons are transmitted. The second wire is then able to turn the moving electrons into an electrical current which produces the same sound that created the moving electrons in the first wire (Gugliotta). Italian inventor, Gulielmo Marconi received the British patent for the radio in 1897. In 1901, Marconi discovered that radio wires did not have to be close to each other to work and that radio signals could be transmitted over very large distances. On December 13, 1901 Marconi successfully transmitted a radio wave 2,000 miles across the ocean from Poldhu, England to St. John’s, Newfoundland. U...
MTC ONLINE, " Reports of Current Experimentation with Microwave and EM Weapons," <http://www.heart7.net/mcf/1.html> (10 August 2003)
Electromagnetic waves are waves that can propagate even though there is no medium. A magnetic field that changes with time can generate an electric field that also changes with time, and an electric field that changes with time can also produce a magnetic field. If the process is continuous it will produce a magnetic field and electric field continuously. If these magnetic fields and electric fields simultaneously propagate (spread) in space in all directions then this is a symptom of the wave. Such a wave is called an electromagnetic wave because it consists of an electric field and a magnetic field that travels in space.
6) Michele Zorzi, “Wireless Sensor and networks: Recent trends and Research Issues’’, University of Padova, Italy, IEEE communication society, Poland, April 28-30, 2008.
Radio-wave technology is one of the most important technologies used by man. It has forever changed the United States and the world, and will continue to do so in the future. Radio has been a communications medium, a recreational device, and many other things to us. When British physicist James Clerk Maxwell published his theory of electromagnetic waves in 1873, he probably never could have envisioned the sorts of things that would come of such a principle. His theory mainly had to do with light waves, but fifteen years later, a German physicist named Heinrich Hertz was able to electrically generate MaxwellÕs ÒraysÓ in his lab. The discovery of these amazing properties, the later invention of a working wireless radio, and the resulting technology have been instrumental to AmericaÕs move into the Information Age. The invention of radio is commonly credited to Guglielmo Marconi, who, starting in 1895, developed the first ÒwirelessÓ radio transmitter and receiver. Working at home with no support from his father, but plenty from his mother, Marconi improved upon the experiments and equipment of Hertz and others working on radio transmission. He created a better radio wave detector or cohere and connected it to an early type of antenna. With the help of his brothers and some of the neighborhood boys he was able to send wireless telegraph messages over short distances. By 1899 he had established a wireless communications link between England and France that had the ability to operate under any weather conditions. He had sent trans-Atlantic messages by late 1901, and later won the Nobel prize for physics in 1909. Radio works in a very complicated way, but hereÕs a more simple explanation than youÕll get from most books: Electromagnetic waves of different wavelengths are produced by the transmitter, and modulations within each wavelength are adjusted to carry ÒencodedÓ information. The receiver, tuned to read the frequency the transmitter is sending on, then takes the encoded information (carried within the wave modulations), and translates it back into the sensory input originally transmitted. Many of the men who pioneered radio had designs for it. Marconi saw it as the best communication system and envisioned instant world-wide communication through the air. David Sarnoff ( later the head of RCA and NBC) had a vision of Òa radio receiver in every homeÓ in 1916, although the real potential of radio wasnÕt realized until after World War I.
David, Leonard. "Proposed Satellite Would Beam Solar Power to Earth." 6 April 2012. Space.com. Website. 18 November 2014.
There are two main types of RFID tags: active and passive. The difference between these two types lies within how and when they transmit their stored information. An active RFID tag is connected to a power source, ge...