Designing 180 degree hybrid only with LC elements

[radiohead]

Hi,

Is it possible to design a 180 degree hybrid just with LC elements, so without any transformer or microstrip structure? Frequency is 30MHz, so TL's are impossible.

 

[flatulent]

Re: 180 degree hybrid

Yes. If you are at a fixed frequency you start with an in phase power divider and add enough low pass filter operating well below cutoff to one output to get the extra phase shift.

 

[djalli]

180 degree hybrid

Lowpass, bandpass, highpass.delay etc. filters would do the trick.

Use Bode Plot drawing to determine Phase shift, poles, zeros and therefore L and C elements. It will be easier if this was a filter. It will become harder because it is not a filter but a filter with LC elements to behave like a 180 degrees coupler.

You have to work out some arraignment in gain of the LC filter so the filter you created works as a coupler too. After Jean Baptiste Fourier is Sir Henry Bode my most favorite guy.

 

[frannk]

Re: 180 degree hybrid

How about a lumped element ratrace. Which is again like a lowpass and highpass as mentioned previously.

 

[radiohead]

Re: 180 degree hybrid

Frannk, this is exactly what I was looking for. A hybrid without losses from power splitters! Thanks