Microwage RF detector
tone
transmitting) working in the 18Ghz region. Any offers especially of the
diode to use.
Thanks
o...@uakron.edu
Ouch, not a common band. This is usually done with a spectrum
analyser.
Unless you have a lot of TX power, you have a problem.
Search for w1ghz antenna book, and look at the 24 ghz ham stuff. You
need a waveguide to sma adapter and then a diode detector module. Ones
that go that high are not cheap. The waveguide will probably have to
be bigger then what is used at 24 so you are not "waveguide beyond
cutoff"
The open waveguide will be a 3dB antenna, not much gain at all. The
transition from SMA to the detector will be about 2 dB of loss, So
your already behind the curve.
Something like this.
http://www.krytar.com/html/planar_doped_barrier_detector.htm
They do show up on ebay, but usually not tested.
Mind you, microwaves are a RF safety issue, don't get your eyes
forward of the dish.
Be aware that high SWR from you sticking a probe in the wrong place
could blow out your receiver front end in some cases.
And even if you do have RF, it doesn't tell you how much or if your
modulating correctly. This is why a RF power meter or a spec an with a
calibrated antenna is used.
In other words, time to find a RF technician or engineer with the
correct gear.
Steve
John Larkin
Why not a simple dipole with a diode at the middle? You could make
that on a slice of fr-4 in a few minutes, for less than lunch money.
Use something like an SMS7621-079 maybe.
http://www.skyworksinc.com/uploads/documents/200041M.pdf
John
o...@uakron.edu
You sure?
Steve
John Larkin
Why not? Things scale. People use dipoles+schottkies at way higher
frequencies than this. The only reason to use FR4 is because it would
be an easy way to solder that _really_tiny_ part down. It would
probably be easier to use real wires for the antenna itself, because
they'd be easy to trim to length to tune the thing. With enough
transmit power, it wouldn't need tuning at all.
A patch antenna would be interesting. Googling that would give lots of
hits. You could hack one on copperclad with an x-acto knife.
That Skyworks diode has Xc around 50 ohms at 20 GHz, a little high but
not lethal. Aeroflex has an 0402 schottky that's only 0.08 pF, which
would be even better.
The problem isn't quantified, so we don't know how much signal we'd
have. Close to a transmitting dish, I'd assume a bunch.
It's surprising what fast stuff you can do with tiny surface-mount
parts on pc boards, things that used to need plumbing.
John
Wimpie
Hello,
With a microwave diode you should be able to detect levels of -30 dBm
(or even significantly lower with good match).
With a 3 dBi antenna this converts to a plane wave power of about 30mW/
m^2 (for example transmitter with 1.5W EIRP at 2m distance).
For this purpose you should use real schottky diodes intended for SHF.
That are the ones with reverse voltages of about 4V or less and
capacitances of 0.25pF or less. An example is BAT15 (smd, not beam
lead). If you can get special mmW diodes (capacitances around 0.1 pF
or less), and tune them, you will get more output voltage with the
same incident Power Flux Density.
To get all EMF generated by the junction, the load should be larger
then the so-called "video resistance" (factor 10 gives you 90% of
EMF). Diodes with relative high forward voltage have high video
resistance and need a buffer (for example op-amp with CMOS input
stage). By doing this, you can use the diode without bias avoiding
thermal issues.
Best regards,
Wim
PA3DJS
www.tetech.nl
remove abc in case of PM
tone
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.
Joerg
> On Tue, 24 Nov 2009 08:30:14 -0800 (PST), o...@uakron.edu wrote:
>
>> John, at 18 on FR4?
>>
>> You sure?
>>
>> Steve
>
> Why not? Things scale. People use dipoles+schottkies at way higher
> frequencies than this. The only reason to use FR4 is because it would
> be an easy way to solder that _really_tiny_ part down. It would
> probably be easier to use real wires for the antenna itself, because
> they'd be easy to trim to length to tune the thing. With enough
> transmit power, it wouldn't need tuning at all.
>
Really tiny? 0.060" length is a mid-size boulder :-)
> A patch antenna would be interesting. Googling that would give lots of
> hits. You could hack one on copperclad with an x-acto knife.
>
> That Skyworks diode has Xc around 50 ohms at 20 GHz, a little high but
> not lethal. Aeroflex has an 0402 schottky that's only 0.08 pF, which
> would be even better.
>
> The problem isn't quantified, so we don't know how much signal we'd
> have. Close to a transmitting dish, I'd assume a bunch.
>
> 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.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
John Larkin
wrote:
>John Larkin wrote:
>> On Tue, 24 Nov 2009 08:30:14 -0800 (PST), o...@uakron.edu wrote:
>>
>>> John, at 18 on FR4?
>>>
>>> You sure?
>>>
>>> Steve
>>
>> Why not? Things scale. People use dipoles+schottkies at way higher
>> frequencies than this. The only reason to use FR4 is because it would
>> be an easy way to solder that _really_tiny_ part down. It would
>> probably be easier to use real wires for the antenna itself, because
>> they'd be easy to trim to length to tune the thing. With enough
>> transmit power, it wouldn't need tuning at all.
>>
>
>Really tiny? 0.060" length is a mid-size boulder :-)
It's really a pain to solder. But I'm thankful it's not a beam lead.
>
>
>> A patch antenna would be interesting. Googling that would give lots of
>> hits. You could hack one on copperclad with an x-acto knife.
>>
>> That Skyworks diode has Xc around 50 ohms at 20 GHz, a little high but
>> not lethal. Aeroflex has an 0402 schottky that's only 0.08 pF, which
>> would be even better.
>>
>> The problem isn't quantified, so we don't know how much signal we'd
>> have. Close to a transmitting dish, I'd assume a bunch.
>>
>> 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.
Oh, here's that other detector diode:
http://www.aeroflex.com/AMS/Metelics/pdfiles/SMS201.pdf
Cute little devil.
John
a7yvm1...@netzero.com
Why not ask the intended receiver's RX power level?
Or a bolometer?
Tim Williams
news:693og5hakrhlo8ofv...@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
TheM
> "John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message news:693og5hakrhlo8ofv...@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
Joerg
> On Tue, 24 Nov 2009 13:18:06 -0800, Joerg <inv...@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.
Wimpie
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
o...@uakron.edu
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300346158694
You need .085 line to the diode, the Vivaldi is designed to use the
coax, minus some outer jacket, as its matching structure.
If you ask Jeff Kruth, microwave surplus vendor extraordinaire , owner
of the above auction, for a detector module and two inches of .085
hardline with the connector to the vivaldi, I'd bet he puts a package
together for you. Should be very inexpensive, and odds are he has a
preamp laying around as well. The detector gets a load resistor and
then goes direct into your voltmeter.
Doesn't the 18 ghz link have have diagnostics? It had to be aligned
somehow......
Steve
John Larkin
wrote:
>John Larkin wrote:
>> On Tue, 24 Nov 2009 13:18:06 -0800, Joerg <inv...@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
John Larkin
<tmor...@charter.net> wrote:
>"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>news:693og5hakrhlo8ofv...@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 don't know about visible, but it's been none in the THz range.
John
Joerg
> On Tue, 24 Nov 2009 17:33:18 -0800, Joerg <inv...@invalid.invalid>
> wrote:
>
>> John Larkin wrote:
[...]
>>
>>> 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.
>
But only if you connected it with one strand each plucked from a
super-fine litz wire :-)
Fred Bartoli
> John Larkin wrote:
>> On Tue, 24 Nov 2009 13:18:06 -0800, Joerg <inv...@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.
>
Uh! IR reflow or hot air for something that big? I routinely do 0201
without anything special. Just a stereo microscope and a metcal but you
sure have those, don't you?
I (almost) just can't imagine anything easier to solder...
--
Thanks,
Fred.
Fred Bartoli
> "John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
> news:693og5hakrhlo8ofv...@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?
>
And package that in a mint black epoxy package? :-)
I think Phil Hobbs wrote something about this when he still was at IBM...
--
Thanks,
Fred.
John Larkin
He was doing THz stuff with some other sort of rectifying junction. I
think schottkies may be too slow for optical wavelengths.
I've seen papers on schottky-based signal samplers that worked to 250,
or maybe 500 GHz.
John
Fred Bartoli
Oh, that's only 0.5THz? How slow... :-)
Now, back to my fast 20kHz sensor design.
--
Thanks,
Fred.
Jim Thompson
I vaguely recall Josephson Junctions ??
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
John Larkin
Oh, goodle thz schottky
They do work up there.
John
JosephKK
<To-Email-Use-Th...@My-Web-Site.com> wrote:
>On Wed, 25 Nov 2009 09:12:09 -0800, John Larkin
><jjSNIP...@highTHISlandtechnology.com> wrote:
>
>>On Wed, 25 Nov 2009 15:26:47 +0100, Fred Bartoli <" "> wrote:
>>
>>>Tim Williams a écrit :
>>>> "John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>>>> news:693og5hakrhlo8ofv...@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?
>>>>
>>>
>>>And package that in a mint black epoxy package? :-)
>>>
>>>I think Phil Hobbs wrote something about this when he still was at IBM...
>>
>>He was doing THz stuff with some other sort of rectifying junction. I
>>think schottkies may be too slow for optical wavelengths.
>>
>>I've seen papers on schottky-based signal samplers that worked to 250,
>>or maybe 500 GHz.
>>
>>John
>
>I vaguely recall Josephson Junctions ??
>
> ...Jim Thompson
Somebody did a 70 GS/s 'Scope with them over 25 years ago. It
required liquid Helium for the JJ. I think is was 6 bits and 4k
sample depth. But that is all i still remember.
John Larkin
"JosephKK"<quiett...@yahoo.com> wrote:
>On Wed, 25 Nov 2009 10:37:45 -0700, Jim Thompson
><To-Email-Use-Th...@My-Web-Site.com> wrote:
>
>>On Wed, 25 Nov 2009 09:12:09 -0800, John Larkin
>><jjSNIP...@highTHISlandtechnology.com> wrote:
>>
>>>On Wed, 25 Nov 2009 15:26:47 +0100, Fred Bartoli <" "> wrote:
>>>
>>>>Tim Williams a �crit :
>>>>> "John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
>>>>> news:693og5hakrhlo8ofv...@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?
>>>>>
>>>>
>>>>And package that in a mint black epoxy package? :-)
>>>>
>>>>I think Phil Hobbs wrote something about this when he still was at IBM...
>>>
>>>He was doing THz stuff with some other sort of rectifying junction. I
>>>think schottkies may be too slow for optical wavelengths.
>>>
>>>I've seen papers on schottky-based signal samplers that worked to 250,
>>>or maybe 500 GHz.
>>>
>>>John
>>
>>I vaguely recall Josephson Junctions ??
>>
>> ...Jim Thompson
>
>Somebody did a 70 GS/s 'Scope with them over 25 years ago. It
>required liquid Helium for the JJ. I think is was 6 bits and 4k
>sample depth. But that is all i still remember.
That was Hypres, a 70 GHz analog bandwidth equivalent-time sampler.
The scope wasn't very practical and they discontinued it. Tek and HP
did the same at room temperature. Their web site is down, so maybe
they are gone.
John