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From: john larkin <jl@650pot.com>
Newsgroups: sci.electronics.design
Subject: Re: Yttrium iron garnet
Date: Fri, 31 May 2024 03:40:28 -0700
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On Fri, 31 May 2024 00:04:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>john larkin <jl@650pot.com> wrote:
>> On Thu, 30 May 2024 21:46:20 -0000 (UTC), Phil Hobbs
>> <pcdhSpamMeSenseless@electrooptical.net> wrote:
>> 
>>> john larkin <jl@650pot.com> 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 guessing they've been completely superseded by now to get to ever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.
>>>> 
>>>> One can't modulate a hundreds-of-mA electromagnet very fast.
>>>> 
>>>> 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.
>>> 
>>> And far, far noisier than the best YIGs. 
>> 
>> Coaxial ceramic resonators have Qs in the thousands, and low tempcos.
>> 
>> 
>If you can find one at the exact frequency you need.  YIGs have a huge
>tuning range. 
>
>IIRC you also said that they’re piezoelectric. 

The CCRs are high-K, usually shorted, transmission lines, not
piezoelectric. Prop delay is a tiny fraction of c. You can TDR them as
such. Z is usually in the 10 ohm ballpark.

>
>I’m not saying that YIG is the answer to everything, but for some things
>it’s amazing and (AFAIK) unique. 

No argument, but they will always be big and expensive slow-tuning
power hogs, which is fine in a spectrum analyzer.

RF synthesizer chips are pretty amazing these days too. They make a
pretty good first LO too, but they are small and cheap.

>
>Sure improves spectrum analyzers!

I wonder if the latest SAs use YIGs. 


>
>Cheers 
>
>Phil Hobbs