Wireless networks have always proved to be beneficial over the untidy and cumbersome wired counterparts. In today’s world, cellular phones have become a basic necessity of life and with such high level of importance for this small device, recharging them has always remained a problem. Depending on the make and model of phone, different ones feature different battery stand and talk time. One common thing is that all the mobile phones have to be charged compulsorily once the battery gets drained out.
How would you like the idea of wireless charging of mobile phones using microwaves? Doesn’t that sound interesting? That means you don’t have to carry the charger everywhere and you don’t have to look around for a power outlet. This method of wireless charging of cell phones is done automatically while you talk on your phone by using microwaves. Consequently, the more you talk on your cell phone, the more it gets charged as you talk.
Concept of Working
The basic design of this kind of wireless charger includes a transmitter and receiver section. The main component in the transmitter is the magnetron. The transmission of a microwave signal is carried out from the transmitter with the message signal by using special type of antennas known as slotted wave guide antenna. The selection of frequency is one of the vital aspects in transmission. In this case, the S-band of microwave spectrum (2 to 4 GHz) is used here for the purpose, 2.45 GHz to be more precise.
Moving the focus to the receiver section .i.e. the mobile phone, the main addition that has to be made to it for this purpose is a rectenna, which is a rectifying antenna to convert microwave signal to DC energy directly. A simple rectenna is easy to construct by using a schottky diode positioned between antenna dipoles (the gain and impedance of the antenna is a serious design consideration). The diode is capable of rectifying the current that is induced in the antenna by microwaves. In fact, rectenna is highly efficient in converting microwave energy into electricity, with possible efficiency levels as high as 90% with regularity. Once electricity is produced, the charging network will save the power into the battery.
There’s another vital part of the receiver circuit, which is a simple sensor, which is just used to find out when the cell phone user is talking over it. Since the main objective of this kind of charging is to charge the phone with the microwave that is transmitted after rectification by the rectenna, the sensor has a vital role in the process.
With the completion of the above setup, the necessity for separate chargers for cell phones is eliminated, thus making charging universal. Such a charging method is greatly beneficial for cell phone users who are also frequent travelers since they can take their phones anywhere even if the place is totally devoid of facilities for charging. The user doesn’t even have to remember that he has to charge his phone since it gets charged automatically every time the person talks over the phone.
As for the mobile phone manufacturers, they can forget about listing the specifications for battery standby and talk time for their instruments. Such a feature is a great sales promoter for the company as well!
In a nutshell, such an innovative method of wireless charging of mobile phones using microwaves offers great advantage to the cell phone users, overcoming the hindrances of the typical wired chargers. This new groundbreaking idea could give a new dimension in the revelation of cell phones.