The energy that comes from the environment examples are wind energy, solar energy, radio frequency energy, heat energy, vibrational energy of the body, etc. Among the large number of these energy sources, a source of energy which is currently great potential to be used also with radio frequency is the frequency range 3 Hz to 300 GHz that means include frequency of TV, GSM, CDMA, 3 g, WiFi, etc. Radio waves are part of the electromagnetic spectrum that is comprised of electric waves and magnetic waves. Radio waves carry information by varying combinations of amplitude, frequency, and phase on the wave. The rise in energy intensity radio frequency wireless technology is being driven by the increasingly growing day. There are radio waves everywhere, since the application on the transmission of radio signals, radar, hand phone, modem, etc.
By taking the basic principle of the Faraday’s law says that the change of the magnetic field will generate an electric field and vice versa, be a principle to create tools that can change the electromagnetic waves in the air into electricity as alternative energy solutions. The tool then called radio frequency radiation frequency scavenger/harvester allows us to harvest electrical energy from the environment is empty, the empty rich environment with radio frequency radiation.
The research team from London, Manuel Pinuela, dkk (2013) makes such equipment, harvesters, electric power from the available radio frequency overflow surroundings (radio frequency harvester). They create is able to capture radio waves that exist in the environment, without a special transmitter, so purely derived from existing radio frequencies in the environment. Imagine, if the electrical energy can come from the environment, then the energy sources will be available at any time, renewable, and free.
Before making a tool radio frequency harvester Pinuela, Manuel and the team measured the intensity of the different types of radio wave lines on each region with the frequency spectrum analyzer, it brings about a subway station area is an area that has the intensity of the radio. Following are the results of the measurement of the intensity of every type of radio wave on 270 existing stations in London. It brings the line of DTV, GSM 900, GSM 1800, 3 g and WiFi.
Obtained results that radio frequency bands that most major GSM frequency is intensitasnya. That is because the frequencies used in GSM mobile phones. We know that Mobile is very widely used, even 1 person can have more than 1 phone. So it can be concluded that radio frequency bands that are most effective and efficient way to utilized is a GSM frequency bands.
Then after learning paths to effectively utilized as a source of electrical energy, then a single radio frequency harvester tool. The tool consists of the antenna, pencocok-series impedance (impedance-matching network), Rectifier (rectifier) which in this case diodes maximum power point tracking, and power storage unit. Following is the display of electric harvesters tool creation Manuel Pinuela and his team,
Used 4 different antenna which shaped the Ribbon (tape) and wire (wire), so there are 8 series, to be able to capture radio frequencies on the GSM 900, GSM 1800, 3 g, and Digital Television. Power generated from each of those tools are:
Can be seen in the chart above that maximum power generated is mikrowatt 7.4/cm3 using antenna form ribbons on the GSM 900. When compared to electricity generation technology that originated in the other environment, then the outcome is as follows.
Manuel Pinuela and the team for the first time proved that the tools they create can be competitive with other renewable energy technologies capable of producing electrical energy, such as heat, vibration body pemanfatan body and so on, also indicates that the potential for the use of radio is defined as a source of electrical energy.
- Manuel Piñuela, Ambient RF Energy Harvesting in Urban and Semi Urban Environments. IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, VOL. 61, no. 7, JULY 2013