Resistive Card Supplier / Waveguide Bow Vane Attenuator design
Resistive Card Supplier / Waveguide Bow Vane Attenuator design
(OP)
I am looking for a supplier for resistive card used in a Waveguide Bow Vane attenuator. I am not sure even what the material is called! All I know is that the resistance is measured in Ohms per square...
Basically I am trying to come up with a simple design for a variable attenuator, so any help there would also be much appreciated. Tunable from 0 to 40 or 50 dB ideally.
Basically I am trying to come up with a simple design for a variable attenuator, so any help there would also be much appreciated. Tunable from 0 to 40 or 50 dB ideally.
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
_________________________________________________________________________Steve is a one man shop.
Work: 858-486-1810
Fax: rcard
Other: steve vekes
E-Mail: astscy@aol.com
or rcard on a circuit board (preferred location)http://www.ohmega.com/OhmPly.html, this is a large company, although we recently tested their rcard values and they were 35% too high.
There is also a manufacturer in Florida, couldn't find the link, they make rcard in small sizes 4"x8" range.
Window coverings to filter the sun are also rcard.
I think you can also use magnetically loaded RAM glued to a circuit board. Ask the standards about that Emerson and Cuming, Cumingcorp., and ARC.
kch
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
Presumably the lossy material thickness is relevant because of the skin depth.
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
It is probably they way the resistive card is used.
A strip of it is placed in the waveguide, secured at each end against one H wall and a pin or screw is used to bow the vane in to the path of the microwave RF, thus attenuating the signal.
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
A key problem is power. If you want to dissipate a lot of power the substrate stability is critical. I think these things can be made from nichrome films on mylar, but I don't know if it would be good for bending, especially if there were a lot of operations.
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
Does anyone know of any smaller amounts available anywhere? Say, a couple feet of 100 Ohm per square?
Thank you
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
Work: 858-486-1810
Fax: rcard
Other: steve vekes
E-Mail: astscy@aol.com
kch
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
Thanks,
Mark
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
kch
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
Also, purchase some home window tinting at your local hardware store. It'll look identical to what you'll purchase for 100x the cost. $20 US for 50 square feet.
I recently purchased two kinds and measured approximately 10 and 30 ohms per square. The window tint also has glue on it, essentially a protective layer to prevent you from scratching the surface. If you scratch Rcard, it'll change your performance greatly, so handle it extremely cautiously since you can not see a scratch and can only measure it electrically.
kch
RE: Resistive Card Supplier / Waveguide Bow Vane Attenuator design
svmicrowave has a standard product in rcard.
http://www.svmicrowave.com/pdf/resistive.pdf
they give a power rating on them too, which is nice.
5" wide pieces.
kch