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Comment by Emrod | Hacker News Reader

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 :)

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As far as I understand it near-field effects stop being relevant at a couple of wavelengths away from the transmitter. For 2.4ghz that would give you what, a meter of distance?

Can you link me to reading material explaining how an antenna can have no sidelobes?

Near-field is only a few wavelengths away when the antenna itself is a half wavelength in dimension. Otherwise you would calculate the size of the near field as a function of the physical dimension of the antenna and the wavelength: r2 = 2d^2/λ.

E.g. The radiating near field of a 2.4GHz antenna about 8 meters long would extend about 1km.

[1] - https://www.giangrandi.org/electronics/anttool/regions.shtml

Thanks for clearing that up!

search up beam forming, phased arrays, collimated beams and metamaterial based beam guides

Right, but even a phased array will give you sidelobes, it's only a question about reducing them, right? Your claim that there are no sidelobes at all seems a bit dubious to me.

Or is there some metamaterial "magic" going on even at the transmitter that I'm not accounting for?

:)) no magic, just solid engineering. There will always be sidle-lobes. The question is how much and what do you do with it.

> There will always be sidle-lobes.

Right, and anybody who knows enough to ask you about sidelobes likely also knows enough to know that too.

That's why, if you reply that "there are no sidelobes" you're only harming your own credibility.

A good reply is something like "there are sidelobes, but they peak at -{believable number} dB and are contained to within {small area}. We believe this is more than sufficient to address sidelobe concerns because of {standards}".

That's a reply that earns trust.

You are right of course. Point taken. Thanks :)

Reads more like he doesn't want to tell you what he's doing with the sidelobes, in case you DO get it.

Whereas the question-train you're on is at a pretty interrogative clip ..

"I'm not disclosing basic performance metrics because you might reverse engineer my secret sauce from the basic performance metrics"? Really? Seems unlikely.

"I'm not gonna discuss the finer details with people on HN who are more than likely able to exploit the same discoveries if I share too much .."

Very feasible.

These aren't finer details, they're basic metrics.

Hypothesis A: they don't want to share basic performance metrics because they contain special secret sauce!

Hypothesis B: they don't want to share basic performance metrics because they suck.

We'll see!

A few comments above you said:

> There are no sidelobes

How do you get around the inverse power law? Is the beamforming that perfect?

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.

relays are passive and require no power. quasi-optics.

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?

Great question! in fact... so good that I cant answer it properly without divulging some of the secret source.

Suffice to say that you are on to some of our more interesting IP ;)

60% end to end efficiency at what distance? It's a function of distance. I'm guessing about 30 meters?

efficiency is not a function of distance when there is no lose in the atmosphere :)

At the moment we are working with about 60% end to end efficiency

If path loss doesn't matter to you then you've revolutionized both communications and war.

There's spread over distance. If you've found a way to prevent spread it's either not free space or a change to the electromagnetics fundamentals. It's a really bold claim to make. But maybe I'm misunderstanding something.

Eliminating path loss has always been relatively easy if both ends never move. I’m assuming they mean negligible spread over the distance tested instead of no spread.

I work with radio, and I'm not sure how exactly you are "eliminating" path loss on any sort of real world link, even ones fixed in position. Even very high gain antennas and very small wavelengths are going to spread the energy out to some degree over any non-trivial distance (most links I work on are 10km+, so maybe your definition of non-trivial distances are different than mine).

> there is no lose in the atmosphere

I know bullshit when someone spells it out for me.

Maybe they found a frequency that is not absorbed by the athmosphere that much. Seems far-fetched with the gas mix that the athmosphere is, but I guess that such frequencies would be company IP.

Instruments that sweep all frequencies have been available since shortly after the dawn of radio and public atmospheric absorption tables have been available for nearly as long. Also, absorption bands tend to be very broad in this region, so after 10 or 20 data points there's nowhere for a magic frequency to hide.

You are correct. There's no magic at work here. We don't break the laws of physics, we just flex them with clever engineering... like most innovators that came before us.

Path loss through free space at these relatively low frequencies (<6 GHz) isn't from air/water vapor losses. It's from diffraction spread.

This company can say all they want about near field tech, but the beam waist diameter relative to wavelength determines the diffraction spread. And that aspect of path loss is proportional to the distance in wavelengths even if there's no "absorption" by the air components. For any reasonable link at 2.4-5.8 GHz the length in wavelengths will be tens of thousands.

The equations governing diffraction are relatively straight forward. We are operating within the near-field (or more accurately in the Frensel range). I'm sure you can do the math and see how focusing a phased array can reduce diffraction at this range :)

Just make sure to do your liability math because in a about a year you're going to have a lot of investors very angry at you.

This reference from 2007 wherr a lab at MIT demonstrated wireless power transfer, may be relevant for explaining inductive coupling and the idea that this is not radiative (far field) power transfer - correct me if this technology is fundamentally different:

https://science.sciencemag.org/content/317/5834/83

Coupling has nothing to do with Emrod tech. Its intrinsically limited to low power and small range. It is also has a much more significant impact on health and safty.

Ok understood. The "near field" comment made me think it was the same thing... I don't understand how this works then (not a criticism, just a walking back from thinking I got it)

line of sight

What frequency or range of frequencies is used?

Typically 2.4 - 5.8GHz

My understanding of wave physics is minimal, but at the strengths you're broadcasting at wont this completely drown out any wifi signals nearby?

No. we are beaming strictly point-to-point in the near field unlike WiFi, Bluetooth, RFIF, etc
Unless of course we are beaming directly at a coms antenna, which we don't plan to :)

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