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?

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

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?

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

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

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.

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?

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?

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