question about waveguide power divider

hi everyone

Waveguide power divider usually has one input and two output.If we want to extend,we can connect it.But its efficiency would get down,when more stages connected.So I want to know how to design direct one-to-N waveguide power divider,especially1-to-4 and 1-to-8.Please give me some hits or paper.Thanks!

best regards
Kezman

you can use the following topology.

Thank you burton!Do you have any papers about it?

I have no paper, but I think you can do it yourself because it is not difficult to design this kind of power divider by using inductive post or inductive window to remove the reflection.