What they've done here is use the very old existing rectenna technology and new types of nanoscale rectenna arrays to capture very low energy radio waves without an external antenna. We're taking -20 dBm or 10 μW.
In the end, I welcome any rectenna advances because if we ever build an efficient optical rectenna it'll blow solar panels out of the water by efficiency. Optical rectennas are like fusion power in just how revolutionary they would be to our energy economy.
Not new indeed. Kinda reminds me of old Nextel phones that you would put a little LED on the antenna and it would blink from the EMI when sending and receiving data.
And low-power really means low powered... Like... milliamps. If you fed an RFID chip directly, you'd need to supply about 1 mW depending on the specific chip... 1 milliwatt...
In order to feed that chip with a transmitter you feed up to 2W. So up to 99.95% losses... It's NOT economical for any other device that isn't super low power.
Hell Qi charging is just as bad. Qi2, newest and greatest... Which you basically have the devices touching only get up to 80% at absolute best efficiency numbers. Every mm you add, drops that number significantly.
None of this is going to enable "battery free" for basically anything that any consumer would care to be battery free. And honestly I wish we wouldn't pump the airwaves with all sorts of garbage just because it enabled the most minimal amount of "convenience" for things that never needed to be convenient to begin with.
A friend of mine was working on a car chassis and that thing suddenly started to receive radio. You could faintly hear it coming from the chassis and not from somewhere else. We thought we were going crazy. Touching the chassis made it go away.
This would be neat for a bunch of passive IoT buttons. No need for a piezo to generate power, good for a couple presses at a time, just simple stuff like that.
Once its implementation is feasible and it can extract the waste energy efficiently, this innovation will enable new types of devices and uses that will be critical for commercial, scientific, medical and personal.
Sounds like it's still more theoretical than realized, at this point. Still, I can't help thinking this would be really cool for something like a watch or hearing aids.
I was a little careless with how I phrased that. They said in the article they've done it, but it's not "realized" in the sense that it's not to a level of practicality that they'd want it to be. It can currently harvest signals to -20dBm, but they think they can get that to -62dBm for greater efficiency.
The main hurdle, according to them, is there's no schottky diode that fits their needs, and they'll have to engineer a new variant (at the nano scale...?). So, still a theoretical possibility on a more practical level, but this is hopeful news nonetheless.
Nah, that was just blasting a microwave beam at a collector. It would work and be meh on efficiency, but also bake everything between the two points...neat innovative theory, bad idea. Tesla was a smart dude, but his bad ideas were left ignored for a reason.
That's not right... He was trying to achieve wireless power through Earth resonance. Which AFAIK is pretty much now completely debunked as never going to work ... but it tracks with Tesla's world view.
It's kind of crazy how much you can build without a complete understanding... There's probably stuff we think we understand now that we really don't and other stuff left to discover.
No, this is transforming focused radio waves into DC voltage using a transceiver, Rather than Tesla's ambient electricity harvested from the atmosphere.
I would find this super cool if it wasnt for the fact that all of the radio frequencies are owned by the military and corporations. Outdoor IoT could be amazing, but it is kind of dead because you cant actually connect it to the internet without laying down cable or using 4G which is horrible for low power applications.
I don't know what kind of idea you are getting. Radio and wi-ifi are waves. The wave is what can be used, you don't care who generated it. To say it somehow the wave is in the air and you just take advantage of it being there to convert it to energy. Doesn't matter what the wave could have been read as. In general a radio station is not going to stop working for a whole region just to stop you from using it.
Technically, a properly tuned receiver that's using the signal for power can create radio "shadows" behind the device. People have also been caught with giant coils in their attic siphoning power from nearby radio stations and high voltage power lines, because they can detect the power draw.