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Old Marconi Patent Inspires Tiny New Gigahertz Antenna
agent elevator writes Gehan Amaratunga and a group of engineers in England noted that the Guglielmo Marconi's famous British patent application from 1900 had an interesting and little noticed detail. It depicted a transmitter linked to an antenna connected to a coil, which had one end dangling while the RF signal was fed to the middle of the coil. That detail inspired them to develop a way to reduce the size of a GHz antenna without significant transmission loss by using dielectrics as the radio wave emitting material instead of conductors.
When asked to comment on his finding, Gohan promptly shouted, "it's over 9,000!".
Marconi's connection to the center tap of a coil with one end not connected worked by broken symmetry? Really? It wasn't just a method of tuning a coil to the correct reactance for a particular frequency?
Bruce Perens.
Hey, people I don't know know if you are aware, but if you take a radar unit, drop the receiver and turn up the power, you can cook FOOD on it to!
excitingthingstodo.blogspot.com
This means that Guglielmo Marconi's hard work was stolen without compensation and he has no incentive to invent anymore. Extends patents to 115 years!
That sure looks darn similar to the schematic for a variable inductor. You often use inductors to balance the feed on an antenna system (usually paired with capacitors) and would seem to make sense. Otherwise why the arrow in the diagram?
I was intrigued. But no, Marconi... that... that makes more sense.
I read the title as "old macaroni patent" on first glance.
comment first, facts later. http://chem.tufts.edu/AnswersInScience/RelativityofWrong.htm
After noting all the reference layout information from my chip antenna vendor, I too noticed they kept adding some sort of 'microstrip' trace that went out from the antenna that they said should be tuned. So I added one, it is amazing how well it works to tune it by scratching the trace at different lengths. Damn, I wish I would have patented that and all its quantum magic... Maybe I'll patent those magic inductor and capacitor I put in front, I am calling it a 'dangling symmetric matching circuit'. And IEEE wonders why I won't join them...
Assymetric- is this about the L-antenna?
What is the range of this? does this span up to 2.4ghz or is GPS just barely in reach somehow?
Uh, the Maxwell equations are perfectly fine for explaining how an isolator/dielectric will generate electromagnetic fields. In fact, the magnetic fields around "displacement currents" like the shifting electric field between capacitor plates are by far the more important part of the Maxwell equations as opposed to the "flow of electron" component since without the displacement current, there would be no electromagnetic wave propagation in the first place.
It looks like the article author fantasized some layman's level explanation of the underlying theory into some fundamental discovery. Probably the actual engineers are embarrassed beyond belief by this nonsense.
Marconi, was a thief. He stole almost all his ideas from Tesla. Maybe this belongs to Tesla too.
Tech reporters should be licensed. I seriously doubt that Maxwell's equations are failing: "Maxwell’s equations explain how high-frequency flows of electrons in conductors generate electromagnetic waves, but they do not explain how an insulating material, where there is no flow of electrons, would also act as an antenna."
The patent detail has nothing to do with the subject. It's a variable coil that's depicted, signalized by the arrow cursor ( like a potentiometer, but a coil)
The article is marketing wank.
aaaaaaa
IEEE is a rotten paywall and should be abolished.
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Yes, Marconi simply provided for varying the inductance. At low frequencies some floating turns have little effect. The coil is physically short in terms of wavelength and there isn't enough stray capacitance to get much resonant or non-resonant current flow through the floating leg.
In some cases people actually short out turns they don't want. That's seen mostly with silver-plated coils in transmitters, where resistance losses associated with the resulting circulating current are sufficiently low. The field from circulating current in the shorted section opposes that of the main section so it helps to reduce the inductance even more than just having fewer active turns would.
They were apparently inspired to try something based on what they thought they saw, but whoever wrote the story at least doesn't have a understanding of Marconi's circuit, the properties of 300 Ohm twin-lead, and maybe not even the requirements for a real-world tv antenna.
It could be that the material they're using conducts at the frequencies of interest exactly as a capacitor does, and with similar current distribution and length it would still have the inductive/radiating properties of a metallic antenna element as well.
If they are using a piezoelectric material near a resonant frequency, the behavior become more like Marconi's entire circuit, with the current through the length radiating from its magnetic field as with a normal antenna, but perhaps achieving the desired low input impedance without having to be near a quarter wavelength long.
Similar properties have been used before in "SAW" (surface acoustic wave) filters which were common in the later analog television sets, but those were not intended to use electromagnetic radiation from the fields associated with internal currents.
https://en.wikipedia.org/wiki/...
SAW filters emulate a complex RC filter network that typically not only has a well controlled bandpass characteristic several megahertz wide for the desired signal, but deep notches (rejection) at key frequencies off both channel edges to avoid interference from the adjacent channels. Like the "super-heterodyne" AM receivers that RCA held Armstrong patents on nearly 100 years ago, filtering is done in a fixed frequencies (around 40 MHz for the SAW tv "intermediate-frequency filters). https://en.wikipedia.org/wiki/...
Channel selection is done by mixing the incoming signals with that of the internal tuning oscillator, the difference-frequency product being the desired signal shifted down in frequency to pass through the filter. To produce the difference frequency product, the mixer can't just add signals, some non-linearity is needed. A circuit producing the product of the inputs actually works best. That's actually much simpler than it sounds, and has the advantage of avoiding the need to retune a complex filter for each desired signal.
SAW filters eliminated many tuned circuits and the need to manually align them in television sets. TV signals not only needed precise control of the frequency response, but the right time-delay versus frequency characteristic as well to avoid horizontal smearing in video. The broadcast NTSC signals were a variation of amplitude modulation where part of one of the sidebands is filtered out to save bandwidth. That introduced non-uniform time delays in the broadcast signal that had to be inversely compensated for in the receiver or the color would be off the right of the monochrome part of the picture etc.
While it is a cute trick to get a tiny antenna resonant and at a workable impedance at well below normal length, it is likely to be of relatively narrow bandwidth (fine for phones but not ordinary tv), and a smaller antenna will capture less receive energy even if the transmit efficiency is fair. Of course cell sites do put out more power than the mobile devices, so a slightly inferior receiver on the mobile side can still be adequate.
... a base-loaded whip antenna?
Didn't Marconi steal the notebook of Jagdish Chandra Bose and came up with the idea of the "coherer"? So wonder where he pinched this idea from.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I take back part of what I said about them not understanding twin-lead. The physical and drive-signal symmetry with twin-lead, or lack of it in a region of something constructed like a SAW filter, can control which area is radiating the signal.
It's easy to be tripped up by some of the wording in the article, like "converted to electro-magentic radiation". It's not really conversion in the usual sense, it's shifting the layout in a way that increases radiation efficiency by avoiding use of the (balanced out of phase) topography that tends to canceling it. 60% radiation efficiency is pretty impressive considering what's involved. Hopefully the crystal won't crack if phones are dropped.
Sometimes. But you're missing what a Counterpoise does.
Bruce Perens.
Thomas Edison didn't patent it so merkins can claim they invented it?
Or the work he stole from Tesla\?
Did you just describe IF Strips without using the term?
I see even classic Slashdot is now pretty much unusable on dial up anymore.