5 ms·

What frequency are you using and over what bandwidth? How many dB down are your sidelobes from your main beam? Are you using parabolic reflectors for your prima

What frequency are you using and over what bandwidth? How many dB down are your sidelobes from your main beam? Are you using parabolic reflectors for your primary antennas, how big are they relative to your wavelength (what's the beamwidth)? What role do meta-materials play, are they the collimating relay? What about the sidelobes on the relay? Why do you think 100 mW/cm^2 is 'safe'? You must know from experience this is enough for tissue heating, even from sidelobes many dB down. Over what ranges do you think this is feasible? With, say 20 km of free space path loss in the 2.4 GHz ISM and 40 dB antenna gain at each end you're going to be at least 50 dB down. Doesn't this mean for things like transmitting power to islands this tech is not useful? Even if you start at 1 KW in (60 dBm), over 20 km the receiving antenna is going to get about 0-10 dBm, or milliwatts. With the same generous setup at 1 km and 1 kW you get 10 watts at the far end. This just doesn't work out.

jsharf 6y ago
Wow, it's cool to see all of the collective knowledge that people bring to hackernews comments. Very interesting questions! Hope Emrod answers them.
mNovak 6y ago
Seconding all the above questions.. For micro-power IoT, maybe there's a play, but bulk power delivery this seems a stretch. In case anyone's wondering, 40dB antenna at either end is reasonably some 14ft across at 2.4GHz, so no small thing.
- Emrod 6y ago
  What are you basing your statement on? have you actually done the math?
  - myself248 6y ago
    https://www.rfwireless-world.com/calculators/Horn-Antenna-Calculator.html https://www.rfwireless-world.com/calculators/Horn-Antenna-Ca... for instance. Put in a 3 by 5 meter aperture, and bam, 40dB on the nose.
  - mNovak 6y ago
    Indeed [1]. For context I design antennas for a living (yes including "meta-materials", AESA, and high power), so not the first wireless power transfer design I've encountered. If this is different, awesome, I'd love to read a whitepaper. All I'm saying is I hope you have a background in EM. There's lots of stuff that sounds great in approximation and models, but breaks down in reality. [1] G=4piA/lambda^2 - I tacked on 70% eff which is mid-high for a parabolic dish
  - TheSpiceIsLife 6y ago
    When you're promoting your own product try not to be a cunt.
    - dang 6y ago
      You posted personal attacks repeatedly in this thread. If you do that again we will ban you. We've had to warn you more than once about breaking the site guidelines already. If someone else is making false claims, show how the claims are false, so we can all learn something. Don't just tell that they're false and especially not in noxious ways like this. Not only do you poison the community when you post like this, you also discredit any truth that you're trying to defend: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sort=byDate&type=comment&query=truth%20discredit%20by:dang https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor... Other commenters have expressed skeptical reactions while staying within the guidelines. Please be like them in the future. By the way, the claims in the OP probably are too good to be true, because most claims are too good to be true. But if we're to have an interesting forum in the long run, people need to correct bad information by respectfully providing good information, not by bashing each other in uninformative ways. Perhaps you don't owe someone who is making false claims better (I'm speaking only of the general case here, not the OP)—but you definitely owe this community better if you're posting to it. Please do better from now on. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
Emrod 6y ago
The antenna size is governed by the wavelength and the distance between Tx and Rx (or relays). There are no sidelobes. We are using near-field and catching close to 100% of the radiated energy. Range is only limited by line of site and an antenna size which is practical. Mind you, we can reduce antenna size and increase range by using passive relays. Using a phased array, operating in the near-field. strictly point-to-point between Tx/Rx. At the moment we are working with about 60% end to end efficiency so sending 1kw means you will get 600w at the far end… not 1w :)
- sroussey 6y ago
  How do you get around the inverse power law? Is the beamforming that perfect?
  - etimberg 6y ago
    Yeah, there aren't enough details here to prove the claims. Not to mention, how much power do the "transmitting relays" use. Those sound like they need to be active devices that require a power source. Yes you can siphon off power from the beam, but with all the losses involved it doesn't seem to make sense.
    - Emrod 6y ago
      relays are passive and require no power. quasi-optics.
      - etimberg 6y ago
        Does this mean that the meta-material lenses are custom built for each relay station? For example, to bend the beam around fixed obstacles like a mountain. Do you believe this will be a barrier to manufacturing and installation? Or are you creating a generic lens that is factory tuneable to the needed characteristics?
        Emrod 6y ago

jsharf 6y ago

Wow, it's cool to see all of the collective knowledge that people bring to hackernews comments. Very interesting questions! Hope Emrod answers them.

mNovak 6y ago

Seconding all the above questions.. For micro-power IoT, maybe there's a play, but bulk power delivery this seems a stretch. In case anyone's wondering, 40dB antenna at either end is reasonably some 14ft across at 2.4GHz, so no small thing.

Emrod 6y ago
What are you basing your statement on? have you actually done the math?
- myself248 6y ago
  https://www.rfwireless-world.com/calculators/Horn-Antenna-Calculator.html https://www.rfwireless-world.com/calculators/Horn-Antenna-Ca... for instance. Put in a 3 by 5 meter aperture, and bam, 40dB on the nose.
- mNovak 6y ago
  Indeed [1]. For context I design antennas for a living (yes including "meta-materials", AESA, and high power), so not the first wireless power transfer design I've encountered. If this is different, awesome, I'd love to read a whitepaper. All I'm saying is I hope you have a background in EM. There's lots of stuff that sounds great in approximation and models, but breaks down in reality. [1] G=4piA/lambda^2 - I tacked on 70% eff which is mid-high for a parabolic dish
- TheSpiceIsLife 6y ago
  When you're promoting your own product try not to be a cunt.
  - dang 6y ago
    You posted personal attacks repeatedly in this thread. If you do that again we will ban you. We've had to warn you more than once about breaking the site guidelines already. If someone else is making false claims, show how the claims are false, so we can all learn something. Don't just tell that they're false and especially not in noxious ways like this. Not only do you poison the community when you post like this, you also discredit any truth that you're trying to defend: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sort=byDate&type=comment&query=truth%20discredit%20by:dang https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor... Other commenters have expressed skeptical reactions while staying within the guidelines. Please be like them in the future. By the way, the claims in the OP probably are too good to be true, because most claims are too good to be true. But if we're to have an interesting forum in the long run, people need to correct bad information by respectfully providing good information, not by bashing each other in uninformative ways. Perhaps you don't owe someone who is making false claims better (I'm speaking only of the general case here, not the OP)—but you definitely owe this community better if you're posting to it. Please do better from now on. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html

Emrod 6y ago

The antenna size is governed by the wavelength and the distance between Tx and Rx (or relays). There are no sidelobes. We are using near-field and catching close to 100% of the radiated energy. Range is only limited by line of site and an antenna size which is practical. Mind you, we can reduce antenna size and increase range by using passive relays. Using a phased array, operating in the near-field. strictly point-to-point between Tx/Rx. At the moment we are working with about 60% end to end efficiency so sending 1kw means you will get 600w at the far end… not 1w :)

sroussey 6y ago
How do you get around the inverse power law? Is the beamforming that perfect?
- etimberg 6y ago
  Yeah, there aren't enough details here to prove the claims. Not to mention, how much power do the "transmitting relays" use. Those sound like they need to be active devices that require a power source. Yes you can siphon off power from the beam, but with all the losses involved it doesn't seem to make sense.
  - Emrod 6y ago
    relays are passive and require no power. quasi-optics.
    - etimberg 6y ago
      Does this mean that the meta-material lenses are custom built for each relay station? For example, to bend the beam around fixed obstacles like a mountain. Do you believe this will be a barrier to manufacturing and installation? Or are you creating a generic lens that is factory tuneable to the needed characteristics?
      - Emrod 6y ago