K parameter in designing multisectionSripline directional coupler

Hello , i am trying to design the coupler described in the attached article.
in order to get the measures in the table shown bellow bellow in need to find the "K" of each section which is linked to the conductuns and inductuns.
how can i pratickly find this "K" for each section.
Thanks
06314061.pdf

I think i solved the problem , K is the coupling so if its -3dB K=0.707

but from the formula bellow we should get the same value of Zo Ze for every section becuase the formula is
i cant see how mathematicky in each section we get a different Ze Zo values ?

Thanks