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TopIntroduction
Now a day, Energy harvesting was the main focus of the research community. There are various sources of power that energy harvesting can gain from. Micro strip patch antennas have been an vast topic for study due to its better configuration which comprises of fine structure, smaller size and lesser weight and more economical. Wireless power transmission holds reliable criteria for future work in generating the electricity for charging mobile wirelessly, as there is no such requirement in placing the cell phones at a very shorter distance to the sockets due to the shorter length of the cable as compared to those of area covered by the wireless field (Crawford, 2005; Parviz, 2009; Tesla, 1905; Warneke et al., 2001). The wireless power system is rapidly expanding, everyone is uneasy to never again have to plug in their devices; simply placing devices on the work surface without any cords is becoming a reality. The major benefits of this system are its Safe, Waterproof, Durability, Aesthetics/clutter etc.
The installation Cost for practical implementation of WPT is quite high. The interference with present communication systems of microwave signals. The conversion efficiency of power to and from is very low. The power, mainly for longer distances, would be really low to do so with a highly directional antenna. (Dickson, 2013; Glaser, 1968; Naresh, 2017a; Naresh, 2017b; Garg, Bhoi, Sanjeevikumar, Kamani, Naresh, Singh, & Bhargavi, n.d.; Garg, Bhoi, Sanjeevikumar, Kamani, Naresh, Singh, Bhargavi et al, n.d.)
The electric energy is transmitted to an electric load without interconnection of wires. It is useful wherever interconnections of wires are inconvenient or not possible. The most commonly used form of WPT has direct induction followed by resonant magnetic induction. Benefits for end users are: Increased convenience (no electric wires), Universal charger (fits all portable devices), Small energy consumption, Prolonged battery life etc. Power is able to be transmitted wirelessly throughout almost all non metallic resources but not limited to solids such as plastics, wood, glass, brick, textiles (Brown, 1964; Dobkin & Weigand, 2007; Shinohara, 2000).
TopWireless Power Transmission
Initially, by microwave, William C. Brown has designed a unit to show the power transfer through free space. At transmitting side, the microwave signals are generated from the source and the output has controlled by the electronic control circuit. At receiving end, antenna circuit receives the power and converts it into DC power. Wireless power transfer is a combined term that refers to transmit energy by means of EM waves. Through microwaves, time varying electric fields, radio waves, magnetic fields, infra-red or visible-light waves can transfer power efficiently. Through Antenna device, input power has converted to an oscillating EM field at the transmitter. It may be an inductor to generate a magnetic field, a metal plate to generate an electric field or an antenna or a laser. At the receiver, a similar antenna which converts the oscillating fields to an electric current. Eq. (1) gives the wavelength (λ) of waves which carry the energy over the gap.
Figure 1. Wireless power transfer System with RF Generator
(1)The efficiency of wireless power system is measured as the power transferred from the power source to the received power. The formula for measuring operating efficiency is given in eq. (2).
(2)