question:about the coupler

both of these are very narrowband if you consider isolation (5%-10%)

If you want wideband behavior, use coupled line types.

if you want big bandwidth and small square
you can use lange coupler

Ring coupler gives more bandwidth than two branch coupler. For barnch coupler the band width can be increased by adding number of branches.

IS ring coupler has so large bandwidth?

here is another idea so called "de Ronde strip-slot coupler paper."

F.C. de Ronde. "A New Class of Microstrip Directional Couplers." 1970 G-MTT International
Microwave Symposium Digst of Technical Papers 70. 1 (1970 [MWSYM]): 184-189.

By using Cohn's slotline in combination with a microstrip. simple 90 as well as 180 directional
couplers of any coupling value can be made. As examples an ultra flat 10 db coupler for 1 - 12
GHz, an octave wide (2 - 4 GHz) magic tee and an almost lumped proximity coupler for 2 - 8
GHz (all on alumina substrate) have been made.

No it is not larger than the bandwidth of a Lange coupler.