Re: Small magnetic tunable filter for 6G and beyond

On Mon, 27 May 2024 13:27:02 -0400, Joe Gwinn <joegwinn@comcast.net>
wrote:

On Mon, 27 May 2024 05:08:40 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
>

To 6G and beyond: Engineers unlock the next generation of wireless communications:
https://www.sciencedaily.com/releases/2024/05/240524114938.htm
Source:
University of Pennsylvania School of Engineering and Applied Science
Summary:
Engineers have developed a new tool that could unlock 6G and the next generation of wireless networks: an adjustable filter that can successfully prevent interference in high-frequency bands of the electromagnetic spectrum.
partial quote:
What makes the filter adjustable is a unique material, "yttrium iron garnet" (YIG),
a blend of yttrium, a rare earth metal, along with iron and oxygen.
"What's special about YIG is that it propagates a magnetic spin wave," says Olsson,
referring to the type of wave created in magnetic materials when electrons spin in a synchronized fashion.
When exposed to a magnetic field, the magnetic spin wave generated by YIG changes frequency.
"By adjusting the magnetic field," says Xingyu Du, a doctoral student in Olsson's lab and the first author of the paper,
"the YIG filter achieves continuous frequency tuning across an extremely broad frequency band."
As a result, the new filter can be tuned to any frequency between 3.4 GHz and 11.1 GHz,
which covers much of the new territory the FCC has opened up in the FR3 band.

>
As with many breathless announcements of breakthroughs, this may not
fare well in reality, for all the reasons mentioned up thread.  But
anyway, here is the full announcement:
>
.<https://blog.seas.upenn.edu/to-6g-and-beyond-penn-engineers-unlock-the-next-generation-of-wireless-communications/>
>
The item about LightSquared is amusingly off-mark:  The problem with
LightSquared was that their proposed ground-based transmissions were
far too strong, and threatened to overwhelm existing GPS receivers, in
particular those in safety-of-flight involved GPS receivers. Inventing
a fancy new filter won't help any more than boring old filter
technologies, as it's the GPS receivers would need to be updated and
recertified, which is a very big deal.
>
I haven't looked, but I bet there is an arXive paper on the yig filter
details.
>
Joe Gwinn

Does satellite nevigation need a low-Q tunable bandpass filter? There
are great SAW-type resonators around with better filtering, no magnets
required.