Practical use of RF power transfer over larger distances

Speaker: Huib Visser

Company/ Institute: Holst Centre

Event: 16th work meeting

Date: 16 October


While RF power transfer over short distances (millimeters) is being introduced now commercially for charging mobile devices, RF power transfer over distances of several meters is still an active research topic. Wirelessly transferring power over such distances opens up the road to employing large numbers of wireless sensor nodes without the need of regularly replacing batteries. Employment may be seen in, for example, greenhouses where we want to know the temperature, humidity and gas
concentration distributions throughout the environment. Other  possibilities may be found in remotely logging temperature data for frozen food being transported. With one or a few RF transmitters, tens to hundreds of distributed sensor nodes may be powered up to distances of 10 meters and beyond.

The design steps in making a small rectifying antenna (rectenna) will be outlined and results will be compared to the state of the art. Imec’s current rectennas can deliver a DC power of tens of milliwatts, during tens of milliseconds every one or two minutes on a distance up to 12m from a RF transmitter. The transmitter operates well within legal transmit power limits. A temperature sensor with LCD display, fed with a small 900MHz rectenna will be demonstrated.

Slides: click here to download (Community members only, login required)