Feeds

back to article Boffins' invisible magnetic ring pieces: Next-gen mobe emitters

German boffins have discovered that two microscopic magnets glued together can create a radio antenna capable of transmitting into the GHz band - where mobile phone signals and other tech lies. The disks are only 500 billionths of a metre wide and 10nm thick, so even once a pair of them are stuck together with a similarly sized …

COMMENTS

This topic is closed for new posts.
Silver badge

Not that I've got anything against blue sky research

but what is this for? You can already achieve Ghz transmission directly from a chip - or you could 25yrs ago when I was looking into voltage boosting using on-chip transformers - which would (probably) have radiated more efficiently than the magnetic ring pieces mentioned.

And you would really 'have to hold it properly' for such a localised source.

0
5
Silver badge
Paris Hilton

Re: Not that I've got anything against blue sky research

"You can already achieve Ghz transmission directly from a chip - or you could 25yrs ago"

These were the chips as big as a dinner plate, I suppose?

0
0
Silver badge

Re: Not that I've got anything against blue sky research

Transmitters are now much larger. Yeah, more than one can be put on a chip, but you need multiple chips if you want to broadcast on all the various worldwide bands. That's one of the reasons why you can't get a LTE worldphone today, let alone in the future when everyone is on LTE. With this you could (assuming they can work out something as small for the receivers)

0
0
Bronze badge
FAIL

magnetic vortices?!

Could've been forgiven for thinking that this was from the timecube school of physics.

0
2
Silver badge
Stop

SI prefixes are useful

"500 billionths of a metre wide and 10nm thick"

Really? Two ways of writing the same unit in one sentence!? Is that helpful?

Answer: NO

9
0
Silver badge
Thumb Up

Re: SI prefixes are useful

Really? Two ways of writing the same unit in one sentence!?

At least both values are in the same measurement system :)

1
0
Silver badge

Re: SI prefixes are useful

but illegal in the register.

3
0
Silver badge

That tractor beam trick is impressive with the magnets!

but if this research brings us more power efficient radios in our phones, that is good news!

1
0
Silver badge

It was really impressive!

I couldn't even see the wires!

2
0
Bronze badge
Pint

Two antenna concepts

Reciprocity - antennas work equally well (or poorly) when comparing their performance in both directions (transmit and receive modes). [There are obvious {LOL} exceptions to this fundamental truth, but this margin^h^h^h^h^h^h comment box is too small to contain the detailed explanation of why reciprocity isn't always true). These exceptions do not apply in this case.]

Capture Area - in receive mode, an antenna can only capture the energy that its physical structure can interact with. In general, a tiny antenna can only capture so much energy. The field whistling over its little head is out of reach.

Combine these two rules and you'll see that, like engine displacement and todgers, size matters.

1
0
Meh

New principle in video?

I don't think there's a new principal at work in the video. I'm not a physicist, but what I think is happening is...

At relatively large distances, the relative strengths of the magnets dominate the resulting net force. However, when you get very close, the relative distances dominate because the force depends on the square of the distance. The gaps between the small magnets allows a closer approach to the central magnet between the small magnets, which is why all the magnets rotate together, as if the outer magnet were enmeshed in a gear wheel. If the small magnets were replaced by a continuous ring, the locking effect would be lost, I think.

A nice demo, but not a patch on a demo of the effects of superconductivity.

2
0
Silver badge
Thumb Up

Re: New principle in video?

I think you've got it right.

0
0
Silver badge

Air bearing?

That second video, he says that to him it's magic. To me it's a frictionless bearing or track - has anything been done with that?

1
0
Bronze badge
Childcatcher

Re: Air bearing?

I think the "frictionless" portion needs some work. It is dependent on the fields of the two magnetic sets which are not uniform. You could see this in the video when the disks maintained their relative position to each other; when one turned, the other moved to stay in the same relative position. This can be used in things like regenerative braking and magnetic suspension can be used to reduce friction, but that does not seem to be what is going on in the video.

0
0
Trollface

Magnets?

How the fuck do they work?

I'm so 4 years ago.

3
0
Silver badge
Thumb Up

Re: Magnets?

I think Richard Boyce above got it pretty much right.

You need a differential between the distances between the centre magnet and the ring magnets and the external magnet, but the internal magnet must be stronger.

The large magnet in the centre of the ring has a stronger overall field so it attracts more strongly further afield.

However, as the external magnet approaches, the inverse square law kicks in and the repulsion of the outer ring magnets increases more rapidly (they are closer) than the attraction of the inner until the attraction and repulsion balance out.

1) If you try to pull them apart, then the repulsion of the outer drops off faster than the attraction of the inner so the inner resists.

2) If you try to push them together, the outer repulsion increases more rapidly than the attraction of the inner, so the outer resists.

If you superimposed two field curves on the same graph, one stronger one and one less so, but displaced the stronger one horizontally, where they intersected would give the balance point.

Quite a cute little experiment, but I'm at a loss as to why the nice old guy can't figure it out.

0
0
Silver badge

Re: Magnets?

skelband, you totally missed the point of elephant's question. (s)he wasn't asking for an explanation of the experiment in the video, just simply: how do magnets work?. In other words, how come a magnet is magnetic?

0
0
Silver badge

Re: Fucking Magnets, How Do They Work?

Miracles.

0
0

Re: Fucking Magnets, How Do They Work?

@Crisp

I think you mean:

MoThErFuCkInG MiRaClEs.

HoNk! :o)

1
0
Silver badge
Thumb Up

Re: Magnets?

> skelband, you totally missed the point of elephant's question.

Ah yes. It is, of course, magic as any fule no.

0
0
Silver badge

Star Trek - tractor beam - amiable old man ?.....

It's Khan!!

0
0

Model of Atom?

In the video the finger is moving the magnet array

At the center is a large magnet (polarity #1)

Around its edge are smaller magnets (polarity #2)

As the finger moves the larger array around another magnet (same polarity as #1) is held at a fixed distance. Is this a model for how electron shells work?

0
0
This topic is closed for new posts.