you use the same techniques. you only switch to lumped components!
quite a time ago there was a paper in QST, describing just what you
need, but it's going to take me sometime to track it and rescan it.
basically it's a bifilar wound inductor with a reactance of 50 ohms at
the operating frequency, with shunt capacitors, also of 50 ohms
reactance shunted across adjacent terminals. not too complicated and
cheap to make. not too wideband though.
Saandy 4Z5KS