US successfully transmits 1.6 kW of wireless power over a distance of 1 km using microwaves

The US Naval Research Laboratory (NRL) has successfully transmitted 1.6 kW of wireless power over a distance of 1 km using microwaves.

The idea of ​​wireless power transmission has been around for a long time. The principle of wireless power transmission is quite simple. Electricity is converted into microwaves, then focused into a beam and “shot” to the receiver, a device made of components called rectenna (rectifier antenna). When microwaves are “shot” and affect the rectenna, the elements will create a DC current.

The NRL team used a 10 GHz microwave beam and set up wireless power transmission testbeds at two locations: the US Army Research Field in Blossom Point, Maryland and HUSIR (Haystack Ultra Wideband Satellite Imaging Radar) at MIT in Massachusetts.

The 10 GHz frequency was chosen because it can transmit in heavy rain conditions with less than 5% energy loss, and is safe to use around animals or humans.

The NRL's wireless power transmission test in Maryland reached 60% efficiency. The Massachusetts test had lower power levels than Maryland, but had a higher average power, so it transmitted more energy.

Wireless power transmission technology could now be used by the US Department of Defense to deliver electricity to soldiers in the field, eliminating the need for fuel transport, which is vulnerable to attack.

In the future, this technology could be used to transmit electricity on the ground, or from space back to earth, providing electricity 24/7/365.