what kind of resistor used in attenuators for 6GHz

[abc123]

ketemicro

What kind of resistor (carbon, chip, metal..) should be used in the attenuator design, for 6GHz with 2 watt power rating as in the fixed attenuators available on the market? the regular SMD chip resistor is only 0.5watts maximum. how they did it?

total attenuation is 20dB. do i need to use several sections of resistor network to reduce the power consumptions of the resistor used?

 

[VSWR]

where are chip attenuators used

**broken link removed**

They have DC-6 GHz attenuators with 5 W rating, which will give sufficient margin. Attenuation from 1 to 30 dB.

 

[FvM]

what kind ressitor

M-S-I (www.mini-systemsinc.com) is another company specialized in microwave resistors and attenuator arrays.

Generally, you can try to assemble attenuators from small chip resistors. Thin film is preferable, more important is to have untrimmed resistor areas. Higher power may be achieved by paralleling some chips. If you see the shape of usual commercial (e. g. with SMA connector) attenuators, it should be pretty clear that they aren't build from individual chip resistors.

 

[biff44]

attenuator 3db resistor network

The material the resistor is made of is not that important. The stray capacitance, both from pad to pad, or pad to ground, is important. For these reasons, it is common to use very small resistors, space very tightly together. Printed resistors are even better, as there are less parasitics.

 

[radiohead]

Power rating depends on size: the bigger the volume, the larger the area over which the heat dissipation can be distributed.

RF performance depends on parasitics. For resistors larger means bigger parasitics worse RF performance.

Other technologies can be used like damped thin-film coaxial attenuators. For example minicircuits has them SMA-connectorized. Good RF performance guaranteed.

If this is not okay find some SMD mounted fixed attenuator pads if it needs to operate up to 6 GHz.

 

[abc123]

http://www.ketemicro.com/pic/SMD%20Attenuators.pdf

They have DC-6 GHz attenuators with 5 W rating, which will give sufficient margin. Attenuation from 1 to 30 dB.

I try to contact them "www.ketemicro.com" but they refused to quote the price of the attenuators & resistor chips I need unless I give them the target price first. they said it will be a waste of time for them if they quote the price and I did not purchase. They are Chinese company.

What is the right market price should be for these attenuators and chip resistor attenuators? (for 500pcs -1000pcs) 2W, DC-6GHz, 20dB.

 

[abc123]

I finally found that Minicircuits has a lot of 1W attenuator chips in tiny ceramic package that goes up to 8GHz, the price is US$2-US$3 each in small quantity. this save me a lot of problems, since all the attenuation values from 1db to 20db is there to choose. I use two 10db attenuator in series to make a 2W 20db attenuator. does it work like this way?

 

[on1aag]

Hi abc123,

No, it doesn't work that way. If you choose to use two 10 dB attenuators,
the first will dissipate 1.8 watts . . . and the second only 180 mW.
It may look a bit silly but you should start with the lowest attenuation
and increase the attenuation when the power has been dropped sufficiently:

1 dB + 1 dB + 1 dB + 2 dB + 2 dB + 3 dB + 10 dB

or

1 dB + 1 dB + 2 dB + 3 dB + 3 dB + 10 dB

Theoretically a 3dB / 1W attenuator would be ok for the first attenuator
but a 17 dB attenuator will probably not be available.
It will always be a compromise between safety margin and costs.
One more advice, once you have built the thing mark where you can
apply the power.

on1aag.

 

[radiohead]

That's true, I remember loading a pcb with some 100 resistors of serialized pi and t attenuators for attainting a distributed dissipation. Calculation can be done easily in excel or consorts with the right formulas.
**broken link removed**

 

[FvM]

Unfortunately, Mini-Circuits has no other attenuators than 10dB/1W. Others suggested in the discussion have, e.g. 20 dB/2W as requested. However, I don't know about price and delivery conditions.

 

[Beulah]

you may refer this website
**broken link removed**

They have DC-6 GHz attenuators with 5 W rating, which will give sufficient margin. Attenuation from 1 to 30 dB.

Added after 31 seconds:

you may refer this website
**broken link removed**

They have DC-6 GHz attenuators with 5 W rating, which will give sufficient margin. Attenuation from 1 to 30 dB.

 

[abc123]

you may refer this website
**broken link removed**

They have DC-6 GHz attenuators with 5 W rating, which will give sufficient margin. Attenuation from 1 to 30 dB.

Added after 31 seconds:

you may refer this website
**broken link removed**

They have DC-6 GHz attenuators with 5 W rating, which will give sufficient margin. Attenuation from 1 to 30 dB.

"Beulah"
As in my previous post, I try to contact www.ketemicro.com to ask them to give me the price quote of coax attenuators and chip attenuators, but they refuse to quote the price to me if I do not give them the target price first, they said it will be a waste of time for them if they quote and I did not buy it. they are Chinese company. "Beulah" do you know what is the price of these chip attenuators ? are they the manufacture or just a trading company?

The Minicircuits web page is :
http://www.minicircuits.com/products/attenuators_sm_fixed.html
looks like they have 2db, 3db, 15db too, I can use 2db+3db+15db to make 20db 2W

 

[FvM]

I previously missed the 1W parts with different attenuation values from Mini-Circuits. The said combination should work. However, as said, M-S-I (see above) has 2W/20 dB in a single part.

 

[abc123]

Found very useful article on the attenuator design.
http://www.w1ghz.org/QEX/Building_VHF_Power_Attenuators.pdf

 

[attenuator123]

Hello VSWR,

Please you let us know your company and contact way. We will check what you said if it's true.

Do you know the reason why did they quote to you?