Path: ...!news.nobody.at!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: Yttrium iron garnet
Date: Fri, 31 May 2024 02:50:29 +1000
Organization: A noiseless patient Spider
Lines: 75
Message-ID: <v3aaov$1p96c$1@dont-email.me>
References: <v368qb$106vv$1@dont-email.me> <v37nll$17q1d$2@dont-email.me>
 <cipe5jtcttecs7r5k9pngm94gqseoo913u@4ax.com> <v393pp$1ihhr$1@dont-email.me>
 <v39g2i$1kegm$1@dont-email.me> <X1Z5O.409$Ktt5.58@fx40.iad>
 <n71h5j5ls6v3u75eg8gr6sni800upq5l4i@4ax.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Thu, 30 May 2024 18:50:41 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="d51a066cbca6b09280003e705595f526";
	logging-data="1877196"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/jylhbkRDJXd2Eq65EA/FDnR+i+1bslvM="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:EjL52SNY7gXGpFbKOH/Pt6aorfk=
In-Reply-To: <n71h5j5ls6v3u75eg8gr6sni800upq5l4i@4ax.com>
Content-Language: en-US
Bytes: 4342

On 31/05/2024 12:04 am, john larkin wrote:
> On Thu, 30 May 2024 11:03:19 GMT, Glen Walpert <nospam@null.void>
> wrote:
> 
>> On Thu, 30 May 2024 09:14:58 -0000 (UTC), Cursitor Doom wrote:
>>
>>> On Thu, 30 May 2024 15:45:21 +1000, Bill Sloman wrote:
>>>
>>>> On 30/05/2024 3:37 am, john larkin wrote:
>>>>> On Wed, 29 May 2024 17:12:21 -0000 (UTC), Cursitor Doom
>>>>> <cd999666@notformail.com> wrote:
>>>>>
>>>>>> On Wed, 29 May 2024 13:52:34 +1000, Bill Sloman wrote:
>>>>>>
>>>>>>> Yttrium iron garnet tuned oscillators were around back then, but
>>>>>>> their 2GHz to 8GHz range was too high for me to count with the
>>>>>>> integrated circuits around then - we had to go the Gigabit Logic's
>>>>>>> GaAs parts to get to 800MHz, and that became the unique selling
>>>>>>> point of the system.
>>>>>>
>>>>>> YIG oscillators were quite the thing back in the day, but I'm
>>>>>> guessing they've been completely superseded by now to get to ever
>>>>>> higher frequencies. Seems we've gone from -
>>>>
>>>> This misses Jan Panteltje's thread "Small magnetic tunable filter for
>>>> 6G and beyond" which is about Yig being used today.
>>>
>>> That article makes it seem like YIG is some revolutionary, new, emerging
>>> technology!
>>
>> Use of YIG filters as a replacement for varactor tuning could turn out to
>> be significant.  2022 Microwave Journal article:
>>
>> <https://www.microwavejournal.com/articles/37980-reinventing-yig-
>> technology-for-microwave-filter-applications>
> 
> The VIDA oscillators still look like giant expensive power hogs. They
> don't specify modulation bandwidth on the data sheets that I see, but
> it must be terrible.

https://www.nature.com/articles/s41467-024-47822-3

makes quite a lot of fuss about them not being power hogs.

> One can't modulate a hundreds-of-mA electromagnet very fast.

In fact they tweak quite a compact permanent magnet stack. How fast they 
can do it isn't discussed (or at least if they did I didn't notice it).

> An LC osc with a varicap is a more sensible VCO. Narrowband, one can
> varicap a coaxial ceramic resonator, or a PCB ring oscillator, or
> something. Cheap and fast.

Varicaps are horribly non-linear. Narrow-band is always easier than 
wide-band, but the YIG tuning scheme is good for at least a factor of 
two frequency range and once you've got that you can use counters to go 
down from there until you run out of dividers

> Of course, it's inherently difficult to modulate a high-Q resonator
> fast, even without an electromagnet in the way.

You don't need an electromagnet to get the fields required. You may want 
a non-conducting permanent magnet to proved the bulk of the field - or 
it might be enough to split your magnetic path into lots of parallel 
wire magnets insulated from one another. There are ferrite permanent 
magnets which aren't all that electrically conductive.

This reads more as if you don't want it to work - it's the sort of 
contribution that gets people chucked out of brain-storming sessions.

-- 
Bill Sloman, Sydney