Path: ...!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Mon, 27 May 2024 23:07:55 +0000 From: john larkin Newsgroups: sci.electronics.design Subject: Re: Small magnetic tunable filter for 6G and beyond Date: Mon, 27 May 2024 16:07:55 -0700 Message-ID: References: User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Lines: 83 X-Trace: sv3-flpyxLFql6erIJCgH3unXxaHEcQmn+e5VkFaTck8Z19yJHic+BjBG+C7EITS7rAFhUZoJJjsj4b90kC!gp1FFueDd+qpdHoSH1YG+ZtEk91FWxT/T8zyMmJ/8DEzIJdh6rgMg41UUfK6WM58bcGM7k0/2XyG!upoNtQ== X-Complaints-To: www.supernews.com/docs/abuse.html X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Bytes: 4671 On Mon, 27 May 2024 22:37:31 -0000 (UTC), Phil Hobbs wrote: >john larkin wrote: >> On Mon, 27 May 2024 12:58:08 -0000 (UTC), Phil Hobbs >> wrote: >> >>> Jeroen Belleman wrote: >>>> On 5/27/24 07:08, Jan Panteltje 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. >>>>> >>>> >>>> YIG filter and resonators have always been a bit exotic. Maybe this >>>> will make them common-place. And more compact, hopefully! The YIG >>>> was tiny, sure, but the magnet wasn't. >>>> >>>> Jeroen Belleman >>>> >>> >>> YIG-tuned VFOs are the champs for low close-in phase noise. My HP 8566B?s >>> noise floor at 1kHz is a good 30 dB better than any SDR-style analyzer. >>> >>> If they manage to get them down to Digikey-level practicality without >>> screwing that up, it would be huge. >>> >>> I wonder if you could use a mag amp sort of structure, with a rare earth >>> magnet biasing some cleverly designed bits of saturable ferrite, plus some >>> small coils changing the effective gap in the magnetic circuit. >>> >>> Fun to think about. >>> >>> Cheers >>> >>> Phil Hobbs >> >> How can one keep a magnetic field stable to parts per billion? > >Normally unnecessary for a YTO, I think. > >> Seems like ambient 60 Hz fields and temperature changes and tiny >> noises in the coil current would dominate. It's hard to regulate a >> current to parts per million. >> > >A well-degenerated BJT with a 2- or 3-pole lowpass on the base makes a deep >sub-Poissonian current source. One of our laser drivers has a noise floor >below -190 dBc/Hz at 400 mA, about 24 dB below shot noise. > >You do have to handle the low baseband somehow, of course. For the laser >driver it’s an op amp and voltage reference, and for the YTO it’s a PLL. > >Cheers > >Phil Hobbs >> > Is the yig phase-locked to an XO? I guess that would make a nice jump-tunable first-mixer oscillator. Something else would have to sweep the IF.