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Nanowire backscatter power harvesters are 11x more efficient

by Mark Tyson on 24 September 2019, 11:11

Tags: Fujitsu (TYO:6702)

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The last time I wrote about battery-less devices powered by ambient backscatter was back in 2013. Fast forward six years and the IoT is now a very familiar industry buzzword - but the problem of powering the billions of connected devices remains. People don't want to have to plug-in or change batteries in all the IoT devices that proliferate, and there will be lots of them – 500 billion IoT devices by 2030, according to Cisco.

Thankfully tech firms and researchers have been busy trying to develop new ambient power harvesting devices, which can be incorporated into sensor networks and similar, so they won't need dedicated power sources. Today the Japan Science and Technology Agency (JST), Fujitsu Limited, and Tokyo Metropolitan University announced a newly-developed nanowire backward diode has achieved more than 10 times the sensitivity of conventional Schottky barrier diodes, described as a 'world first'.

The new nanowire backward diode can covert low-power microwaves, which abound in our environment as radio waves, into electricity. It is much more sensitive than conventional diodes, and therefore much better at harvesting this background source of electricity.

In testing the new technology in the microwave frequency of 2.4GHz, which is currently used in the 4G LTE and Wi-Fi communication line standards for mobile phones, the sensitivity was 700kV/W, roughly 11 times that of the conventional Schottky barrier diode (with a sensitivity of 60KV/W). Therefore, the technology can efficiently convert 100nW-class low-power radio waves into electricity, enabling the conversion of microwaves emitted into the environment from mobile phone base stations in an area that is over 10 times greater than was previously possible (corresponding to 10% of the area in which mobile phone communications are possible). This has led to expectations that it can be used as a source of power for sensors.

Microwaves with a power level of 100nW and upwards can be converted into electricity thanks to the nanowire which is about a thousandth of the width of a human hair. The researchers now have high hopes of refining the nanowire diode design, and the radio wave collecting antenna, to implement power control for constant voltage. Such radio waves are emitted by4G LTE, 5G, and Wi-Fi devices that are already commonplace. The new nanowire devices are thus hoped to be instrumental in ushering in the true IoT era.

More details of the nanowire diode research will be revealed at the European Solid-State Device Research Conference (ESSDERC) in Poland on Thursday.

 


HEXUS Forums :: 14 Comments

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Didn't fully understand a word of that, but it sounds something like “stuff what dun't need batt'ries”…?
If so, then that sounds really quite cool.
Oooooh, now this is exciting!

I can imagine entire digital farmlands with sensors powered by the local radio mast and other benign stuff!
Will this not have an adverse effect on the waves it takes power from? Those microwaves are being used to transmit data, so won't this lower the effectiveness of the wifi/data coverage in that area as it's being absorbed?
ValkyrieTsukiko
Will this not have an adverse effect on the waves it takes power from? Those microwaves are being used to transmit data, so won't this lower the effectiveness of the wifi/data coverage in that area as it's being absorbed?

I don't think so, same a tv aerials, tv's don't drag down the quality (hah, wrong word) of the other peoples reception.
ValkyrieTsukiko
Will this not have an adverse effect on the waves it takes power from? Those microwaves are being used to transmit data, so won't this lower the effectiveness of the wifi/data coverage in that area as it's being absorbed?

By taking power from one part of the wave it does not affect the rest of the wave. What could happen is any devices behind a device between it and the antenna would have a dramatically reduce signal strength.

But this technology is not a sinkhole for the whole signal, it only picks up from the wave at the part it has been hit by.

In short, no, it would not have an adverse affect as a whole.