Successful experiment with wind power 

Scientists have developed an antenna based on metamaterials that can
generate electricity from the ever-present radio waves, Wi-Fi, radio broadcast
signals, and radiation from mobile phone towers. In the form of electromagnetic
radiation, these energy-filled waves are all around us. Now with a new
invention, we will soon be able to operate low-cost sensors, LEDs, and other
devices with the help of wind. Jiang Fengzhou, head of a research team at the
University of Southern Florida, and his colleagues developed the system. 

image by MIT News

says that because currently low-cost devices can be operated, they could play a
significant role in the energy of an environmental sensor that records the
temperature in the building, its structure, or the humidity in the forest. The
reason is that it is impossible to go to these places and change the battery
again and again. In the first phase, it generated 100 microwatts of electricity
from low-intensity radio waves that could run simple devices. It has since been
tested in a laboratory. 

It is kept in such a chamber, where outside radio waves
were blocked. While radio frequencies were sent from only one source. According
to critics, the antenna is still very large, which is being considered shrinking.
However, it also generates some energy from Wi-Fi and BlueTooth signals.
However, Professor Jiang believes that now is the time for this technology to
be fruitful because we have special materials and technology. The day is not
far when we will be able to convert the energy lost in the form of radio waves
back into electricity. He added that the first specimen or prototype is 16 cm
long and as wide. It can generate electricity from any frequency between radio
waves of 0.7 to 2 GHz. If placed 100 meters away from the cell phone tower, it
can generate 100 microwatts of electricity.