isolation resisitors in wilkinson coupler

hi, i am using corporate arrangement of wilkinson coupler to split an input power into 4 ports(Equal division) and 4 power amps are used each with an output of 2Watts.
My question is that the isolation resistors used need to be power resistors or ordinary resistors will serve the purpose,keeping in mind that there might be the case that a power amp might fail.

Hi,

yes, they have to be power resistors, higher power rate at output combiner than input divider. Perhaps the exact power rating can be calculated by some formula available that I am not aware of, but I think it can also be easily determined by simulations.

flyhigh

i am doing simulations in ADS and havent been able to work out the procedure to determine the power ratings for resistors. it would be nice, if u eleborate it a bit more.

Hi

If you for example have a two way wilkinson power splitter, and one output is disconnected. Half of the power is transmitted to one port and the other half is dissipated in the isolation resistor.

Regards

hi,

can a wilkinson power divider be used as a combiner and what are the steps to design it in ADS?
any study material would be helpful.

Hi

Sure the Wilkinson can be used as a combiner. Check the S-parameter matrix in any textbook for the Wilkinson. (Pozars book).

Regards

Wilkinson as a power divider doesn't stress the isolation resistor, cos the signal in both branches has the same amplitude and phase, so the potential over the resistor is equal zero. In the case, that one amplifier burns, that output will reflect the half of the power from generator (Wilkinson halved it on input) and half of that power will dissipate in resistor (quarter of the input power) as wrote tyassin.

Hi,

A conservative design for a Wilkinson splitter would take into account that in the worst condition, when both ouputs are completely unmatched and with the worst phase, all the power entering the splitter would be dissipated in one resistor.
Regards

Z

y should use the power resistor, or the IMD shall be very poor when combine 2W rf power

hi
well i'm very interested in this subject, well i need some documentation in friensh or english about " wild band wilkinson devider "
well all i find is simple devider wilkinson but i want the wild band ...
thank u

in AWR, there is a example for wideband power splitter