High-Power RF Multiplexer - Page 3

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Re: High-Power RF Multiplexer



Quoted text here. Click to load it
tml
Quoted text here. Click to load it
There is a way to deal with that, use a shunt mode regulator.  Nearly20%
constant power draw.  And a relatively big "swamping" capacitor.
Quoted text here. Click to load it

Re: High-Power RF Multiplexer


Quoted text here. Click to load it

It looks like I would need to use an RF Directional Coupler type of
architecture, to divert a portion of the RF power to the RF-to-DC
converter.  There's a nice-looking discussion of transformer-based RF
directional coupler design (with free software) at
http://michaelgellis.tripod.com/direct.html .

Would it work to use a "standard" lab-type directional coupler, with
50 Ohm ports (assuming the ports are each rated for enough power)?
i.e. With a coupled port that has 10 dB loss, it should give 2.5 Watts
from the 25 Watts in, which would have a peak voltage of 15.81 Volts,
which might be just enough.

Re: High-Power RF Multiplexer


Quoted text here. Click to load it


Yes, you can do that as well. But all that adds cost because now you
have to install yet another module. Question: Is this for a product or
just a one-time thing where cost really doesn't matter much? What's the
total frequency range over which it must perform?

--
Regards, Joerg

http://www.analogconsultants.com /

We've slightly trimmed the long signature. Click to see the full one.
Re: High-Power RF Multiplexer


Quoted text here. Click to load it

Hi Joerg,

It's not for a commercial product and is for support of a very good
cause.  But if it looks like it would work well-enough we might use
over a hundred of them.  So unit cost would eventually be a concern.

For the operating frequency, we can make it a little easier and say
that it would probably be a fixed frequency band of about 100 MHz
width, somewhere between 1 and 2 GHz.

Right now, I want to try to decide how feasible it might be, and would
like to try to decide how it should be done, and then try to get a
couple of engineering development models designed and built.

Regards,

Tom

Re: High-Power RF Multiplexer


Quoted text here. Click to load it

See the other post. I'd pick a diode, then simulate things on SPICE.
Then build up the rectifier part. Now pick a buck converter chip, and if
you use one from LTC you can simulate that as well. This leads to a
better design confidence before building stuff. But buck regulators are
really run-of-the-mills these days, no need to simulate until the cows
come home.

But keep in mind the AM modulation of the RF signal that this causes.

--
Regards, Joerg

http://www.analogconsultants.com /

We've slightly trimmed the long signature. Click to see the full one.
Re: High-Power RF Multiplexer



Quoted text here. Click to load it

Lots of people, like mini-circuits, make packaged pin diode RF
switches.

John


Re: High-Power RF Multiplexer


On Dec 5, 1:58A0%pm, John Larkin
Quoted text here. Click to load it

I didn't see any at min-circuits' website that meet the specs.

Re: High-Power RF Multiplexer


Quoted text here. Click to load it


I don't think Mini-Circuits has switches for the power levels you
mentioned. Got to roll your own. Solutions "in a can" would be quite
expensive.

--
Regards, Joerg

http://www.analogconsultants.com /

We've slightly trimmed the long signature. Click to see the full one.
Re: High-Power RF Multiplexer


On Sun, 13 Dec 2009 08:30:33 -0800 (PST), Tom Gootee

Quoted text here. Click to load it

Then look elsewhere.

John


Re: High-Power RF Multiplexer


On Sun, 13 Dec 2009 09:50:12 -0800, John Larkin =

Quoted text here. Click to load it

Wasn't there a recent thread where 100 W, GHz PIN diode switches20%
were discussed?

Re: High-Power RF Multiplexer


Quoted text here. Click to load it

You do realize of source, the switching will produce sidebands relative
to the rate of switching? This would be relevant if you are feeding an
antenna for communications purposes.

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"

We've slightly trimmed the long signature. Click to see the full one.
Re: High-Power RF Multiplexer


Quoted text here. Click to load it

Interesting point.  Luckily it shouldn't matter much, for my
application.

Thanks,

Tom

Site Timeline