We cannot imagine the world without electric power. Generally power is transmitted through wires, however there is an idea to eradicate the hazardous usage of electrical wires which involves a lot of confusion particularly in organizing them. Some of these devices might not even need their bulky batteries to operate.

Here are the techniques of transmitting power without using wires with an efficiency of about 95% with non-radiative methods, due to which it does not affect the environment.

In any system of coupled resonators there often exists a so-called “strongly coupled” regime of operation. If one ensures to operate in that regime in a given system, the energy transfer can be very efficient. Scientists have tried to develop methods of wireless power transmission that could cut the clutter or lead to clean sources of electricity.

The attempt to transmit power wirelessly is not new. A revolutionary attempt towards this was made by Nikola Tesla by inventing the wonder of physics, The Tesla Coil, was built with an aim to provide electricity without wires but it failed miserably due to many drawbacks which made it highly uneconomical.

Quick Physics: The Tesla coil creates an electric field that pushes electrons through the light bulb. This is the same way the lights in your house work, except in your house, the electricty comes through a wire instead of through the air.

A Tesla coil makes electricity, which is basically flow of charges. If a fluorescent light bulb is held near the coil, the electricity will then go through the light bulb to the ground, which makes it light up.

The modern Techniques developed so far

Short distance induction

These methods can reach at most a few centimetres. The action of an electrical transformer is the simplest instance of wireless energy transfer. The primary and secondary circuits of a transformer are electrically isolated from each other. The transfer of energy takes place by electromagnetic coupling through a process known as mutual induction. This method is known as inductive coupling.

Moderate distance

Since a magnetic field spreads in all directions, making a larger one would waste a lot of energy. An efficient way to transfer power between coils separated by a few meters is that we extend the distance between the coils by adding resonance to the equation, i.e. the frequency at which an object naturally vibrates. It’s easy to get objects to vibrate at their resonant frequency. This process is known as Resonant inductive coupling

Long-distance Wireless Power

The secret to the SHARP’s(the unmanned plane’s) long flight time was a large, ground-based microwave transmitter. The SHARP’s circular flight path kept it in range of this transmitter. A large, disc-shaped rectifying antenna, or rectenna, just behind the plane’s wings changed the microwave energy from the transmitter into direct-current (DC) electricity. Because of the microwaves’ interaction with the rectenna, the SHARP had a constant power supply as long as it was in range of a functioning microwave array.


The crucial advantage of using the non-radiative field lies in the fact that most of the power is not picked up by the receiving coil, remains bound to the vicinity of the sending unit, instead of being radiated into the environment and lost. With such a design, power transfer for laptop-sized coils are more than sufficient to run a laptop that can be transferred over room-sized distances nearly omni-directionally and efficiently, irrespective of the geometry of the surrounding space, even when environmental objects completely obstruct the line-of-sight between the two coils. As long as the laptop is in a room equipped with a source of such wireless power, it would charge automatically, without having to be plugged in. In fact, it would not even need a battery to operate inside of such a room.


Wireless Power Transmission: An Innovative Idea