Technology has been increasing tremendously for the past one decade. Many inventions have been made, many technological revolutions happened.
Work is becoming easy with the help of electronic gadgets. It’s very common that as the need for electronic or electrical equipment increases, the need of electricity also increases. Because of which, from decades we have been inventing new methods for the energy conversions.
We already know the conversion of electrical energy made possible with the help of the wind, flowing water, sun etc. And also we are creating electrical energy from Nuclear plants, fossil fuels. But there is another way too.
Have you ever thought we can use Electro Magnetic energy for the conversion of electrical energy? This dream of Tesla has made possible by using a device, called, “Rectenna”.
Over the past 2 decades, we are using wireless communications. But most of the energy is going to be wasted. Harvesting of this energy can be possible by using this Rectenna device
Rectenna’s abbreviation is Rectifying Antenna. It is actually a receiver antenna so it is used in the receiving section. So this device is used in the wireless power transmission
Wireless Power Transmission means transferring of energy from one place to another. For near field transmission, we already have electromagnetic induction and air ionization techniques etc. For far field power transmission, there are two methods. 1.Microwave transmission (2). LASER Transmission.
In the Microwave transmission, we use Rectenna in the receiver section to receive the signals and convert them into DC electrical energy.
It had started here:
In the year of 1899, Tesla introduced and demonstrated the concept of Wireless Power Transmission. He described a method of “utilizing effects transmitted through natural media”. This method has been brought particularly into prominence in recent years. Tesla from his oscillator with the frequency of 150kHz lighted two light bulbs. But this was unsuccessful for the commercial use. Because this transmitted power with 150KHz was radiated in all directions. And this Rectenna was invented by William C.Brown.
When an Electro-Magnetic wave hits the rectenna, those are collected by it and the rectifying diodes convert the received wireless energy into DC power. The low-pass filter, which we use in this, will match the load with the rectifier and block the high-order harmonics generated by the diode in order to achieve high energy conversion efficiency because this conversion efficiency is the most important parameter of such a device. According to an experiment conducted, at the operating frequency of 2.45GHz, rectenna has the 85% conversion efficiency, which is more when compared to the other operating frequencies.
The diode use here is a Schottky diode but not a silicon diode. Because Schottky diode has a low forward voltage drop and very quick switching action. The Schottky diode has a forward voltage up to 150 to 400mV while the silicon diode has 600 to 700mV. So, for the fast switching action, Schottky diode is used.
Solar Power Satellites:
Solar Power Satellite is the example for WPT(Wireless Power Transmission).
We arrange solar panels on the satellite. These observe energy from the sun light. This is converted into Microwave signals and given to the Microwave Transmitting system which transmits the Microwave signals to the earth. We arrange the Rectenna at any place on the earth. The given Microwave signals will directly hit on the Rectenna, afterward conversion of energy will be processed inside.
The above-shown image is the picture taken in the United States. And that round shaped one in the image is the rectenna which is about half mile in diameter. It receives 95% of microwave power and U.S getting 5,000 MW of power through this.
Why do we need this conversion while many other techniques are being used?
1.When there is no wind, wind turbines do not work.
2.Nuclear plants release toxic wastages but this conversion process does not.
3.Fossil fuel does not serve electrical power to us many years due to reducing in carbon fuels such as coal amount for the conversion purpose. And it produces carbon dioxide to the environment
4.No solar energy in the night time using solar panels and they might have been influenced by the factors such as clouds etc ( It is experimentally proven that the solar panels on satellites get 10times more energy from the sun than the energy received by the solar panels on the earth)
And this Wireless Power Transmission using Rectenna is very advantageous as it is efficient, fast, and also the need for wires, grids and substations etc can be eliminated. But when we take into consideration of Radiation and Initial cost it is disadvantageous.
Rectenna can be used in wide range of applications like in future it can be used for charging of mobile, running of vehicles, and can get electricity for total home requirements.