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From: Tim Williams on 24 Nov 2009 19:38
"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message
news:693og5hakrhlo8ofvf4qs7q1rv52sisnr5(a)4ax.com...
> Why not? Things scale. People use dipoles+schottkies at way higher
> frequencies than this.

Have they done it monolithic yet? Should be fairly simple to, say, lay down
an aluminum dipole on top of SiO2 dielectric, on top of fairly conductive
(n+?) silicon, for a not-too-awful antenna element, then put a rectifying
schottky junction in the middle, plus tracks leaving the site for power out.
Then repeat the array a brazillion times. Then, scale it down, so the
antenna is around 800nm wavelength or so (should be possible with today's
newest processes?). Does that work?

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms


From: TheM on 24 Nov 2009 19:50
"Tim Williams" <tmoranwms(a)charter.net> wrote in message news:X%_Om.45612$Wd1.21792(a)newsfe15.iad...
> "John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:693og5hakrhlo8ofvf4qs7q1rv52sisnr5(a)4ax.com...
>> Why not? Things scale. People use dipoles+schottkies at way higher
>> frequencies than this.
>
> Have they done it monolithic yet? Should be fairly simple to, say, lay down an aluminum dipole on top of SiO2 dielectric, on top
> of fairly conductive (n+?) silicon, for a not-too-awful antenna element, then put a rectifying schottky junction in the middle,
> plus tracks leaving the site for power out. Then repeat the array a brazillion times. Then, scale it down, so the antenna is
> around 800nm wavelength or so (should be possible with today's newest processes?). Does that work?
>
> Tim

I believe that's been done actually, someone wrote about this here in this
NG some years ago. It'd be very interesting to read what happened with
that project.

M


From: Joerg on 24 Nov 2009 20:33
John Larkin wrote:
> On Tue, 24 Nov 2009 13:18:06 -0800, Joerg <invalid(a)invalid.invalid>
> wrote:
>
>> John Larkin wrote:

[...]

>>> It's surprising what fast stuff you can do with tiny surface-mount
>>> parts on pc boards, things that used to need plumbing.
>>>
>> That is true. Except the stuff inside the sampler heads you showed us,
>> that probably won't fly with SMT packages.
>
> Agoston Agoston showed me a 20 GHz sampler he did, surface-mount parts
> on FR4. A lot of stuff that used to be hybrids can be done now surface
> mount, too.
>

True. He seems to be a guy who rolls up his sleeves and gets stuff done.
It is similar with phenolic. Lots of people say it ain't any good for
anything past audio. Wrong. I have a few VHF/UHF splitters here that are
done in two-layer phenolic.

The first 144MHz transistor power amp I ever built was also on phenolic
because back in those university days buying FR4 would have required
tapping the beer kitty and that was off limits.


> Oh, here's that other detector diode:
>
> http://www.aeroflex.com/AMS/Metelics/pdfiles/SMS201.pdf
>
> Cute little devil.
>

But that really needs IR reflow soldering or at least a hot air station.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
From: Wimpie on 24 Nov 2009 20:54
On 24 nov, 21:50, tone <ax...(a)btinternet.com> wrote:
> tone wrote:
> > I am looking to build a simple RF detector (to prove a microwave dish is
> > transmitting) working in the 18Ghz region. Any offers especially of the
> > diode to use.
>
> > Thanks
>
> Thanks for all the FB. I am starting to think it's more trouble than
> it's worth. I was thinking of a small unit (0.6" aerial, diode and meter
> - maybe even a cap) which when in the vacinity ~2m would detect the rf
> from the dish (0.3-0.6m dish) - certianly not in front.

Hello,

I don't know the power of your uwave unit, but when it is a data link,
you will not have sufficient EIRP in the side lobes to detect with a
simple detector with low directivity antenna.

So best is to check the equipment's data first and do some math before
spending time and money.

Best regards,

Wim
PA3DJS
From: John Larkin on 24 Nov 2009 21:24
On Tue, 24 Nov 2009 17:33:18 -0800, Joerg <invalid(a)invalid.invalid>
wrote:

>John Larkin wrote:
>> On Tue, 24 Nov 2009 13:18:06 -0800, Joerg <invalid(a)invalid.invalid>
>> wrote:
>>
>>> John Larkin wrote:
>
>[...]
>
>>>> It's surprising what fast stuff you can do with tiny surface-mount
>>>> parts on pc boards, things that used to need plumbing.
>>>>
>>> That is true. Except the stuff inside the sampler heads you showed us,
>>> that probably won't fly with SMT packages.
>>
>> Agoston Agoston showed me a 20 GHz sampler he did, surface-mount parts
>> on FR4. A lot of stuff that used to be hybrids can be done now surface
>> mount, too.
>>
>
>True. He seems to be a guy who rolls up his sleeves and gets stuff done.
>It is similar with phenolic. Lots of people say it ain't any good for
>anything past audio. Wrong. I have a few VHF/UHF splitters here that are
>done in two-layer phenolic.
>
>The first 144MHz transistor power amp I ever built was also on phenolic
>because back in those university days buying FR4 would have required
>tapping the beer kitty and that was off limits.
>
>
>> Oh, here's that other detector diode:
>>
>> http://www.aeroflex.com/AMS/Metelics/pdfiles/SMS201.pdf
>>
>> Cute little devil.
>>
>
>But that really needs IR reflow soldering or at least a hot air station.


Oh quitcherbitchin. It's ZERO POINT ZERO EIGHT PICOFARADS.

John

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