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[SOLVED] help to design a 55-65MHz quadrature 3dB coupler

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fxhfzy

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build quadrature couplers

I need to design a 55-65MHz quadrature 3dB coupler for my balanced amp,maybe I have to use coax to build the circuit for the low frequency, is there anyone could give me some reference on how to build a low frequency coaxial hybrid?
 

ferrite quadrature coupler

Hi

Building coaxial quadrature hybrid for such a low frequencies will result in a hybrid as big as a lab! You are better off considering lumped circuit version.

flyhigh
 
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lumped quadrature coupler

Hello!
I am really new to RF,and I can't find any useful information on designing coupler of such a low frequency.
Could you give me some reference?How to do that with lumped elements?
 

make 3db coupler

At those frequencies hybrid couplers can also be realized by using ferrite tranformers as usual..
 

3db coupler design

Could you give me some reference,like paper or application note?
Thank you!
 

lump elements hybrid couplers

You can build as other people said a Lump element hybrid, at your frequency lump components will work fine.

I attach a pdf that has the equations and circuit diagram for your hybrid. Make sure when u build it u put everything symmetrical and as close as possible. Also better use SMD components for the Cs and Ls. If u want to have coaxial feed, just strip a coaxial line connect the inner core to your input and the cover to the ground and you can then connect it to your amplifier on any other component.

That design has about 20% bandwidth.
 

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    fxhfzy

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quadrature coupler ferrite

Thank you!
I forgot to tell you that the output power of the amp is 200W,my mistake.
could you give me a circuit built with coaxial line which can withstand the power better?
 

design coaxial 3db hybrid couplers

I've simulated the circuit in ADS,the amplitude unbalance is +-0.7dB, I think this is too high to get a good system performce,do you have a circuit with better amplitude imbalance?
 

fxhfzy said:
Thank you!
I forgot to tell you that the output power of the amp is 200W,my mistake.
could you give me a circuit built with coaxial line which can withstand the power better?
Click to expand...

that small detail of 200W changes everything. Sorry but for that high powers I cant help.
 

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