wilkinson power combiner

Questions about using the Wilkinson Power Divider as the Power Combiner...

Since from the theory, the Wilkinson Power Divider S parameter for the single input to two output is -3 dB, so there is no loss associated with the power dividing function.

But if it is used as power combiner, from the output to the input, the S parameter is also -3 dB, does it mean half of the energy is consumed by the resistor inside? If so, are there any other form of perfect power combiner that we can use in the microwave frequency?

Thanks.

You don't have any loss when you combine a signal in a Wilkinson divider (except the losses from the line attenuation). If u don't want to use a Wilkinson you can use any other type of coupler to combine powers as Rat Race, 90deg Hybrid , Lange etc. All will do the same for you.

YOu do have losses if you are not combining the same signal. You will get double your power out the output port if you put the same signal into the import ports.

(Prove it to yourself hook up two back to back)

But if you only put one signal in you will get resistive losses because the Wilkinson power divider works by using a resistor to unite the lines again.

So yes you will see -3dB loss if you only have one signal but this is not true if you have two of the same signal.

Thanks for your guys reply. So if the two inputs are co-phased, the power will simply add up... Hopefully my understanding is correct~

Yes that is correct if they are in phase (and amplitude) you will have double the power the the output end ans you have at either of the two input ends.

Good luck

The signals must be coeherent in phase and amplitude.

When they are in phase and amplitude, the votage potential at each end of the resistor is the same so no power is dissipated.

Rod

good way to put it rod!