high power lange coupler
You could do it on a PCB with heat sink, thermal vias, and standard SMT parts. You must calculate the attenuation per stage (of cascaded stages) to result in even power distribution over each stage, for example 1 dB + 2 dB + 3 dB + 4dB = 10 dB.
You could also do it as one stage but it would have to be thin or thick film on aluminum nitride or possibly alumina. In order to spread out the heat requires large resistive area so it tends to become distributed, at which point you need an EM simulator. You can also get hot-spots which will be evident by the current distribution. I have done high frequency, high power lange coupler with 50W termination on aluminum nitride. Sonnet was used to optimize thin film shape (get rid of hot spots), then brought into ePhysics via HFSS for thermal analysis.
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