High power splitter using microstrip waveguide

I try to do the small project whichd design power splitter as picture below which using microstrip waveguide.
I don't know what must be consideration for the design. Pls make me a suggestion, power approach 500W at frequency of 200Mhz.
Thanks

The main problem is that a microstrip is not designed to transmit such power level. Suitable connectors like SMA are also not rated for such power level.
Another problem is the mismatch on the transmission line; then, voltage an current nodes exceed the limits, the thin center conductor melts and breakdowns occur at narrower gaps as well as through the dielectric.

To split 500 W at 200 MHz, use a strip line (not microstrip), or a coaxial line design. Try to follow Matthaei et al.: Microwave Filters.

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BTW, your picture shows a "full" strip line, ot the microstrip.

The strip line in waveguide need to be designed in HFSS or CST software.

Where to get the material?

I haven't got the right answer.