Harmonics problems on Lattice-type LC Balun

I am trying to combine the power from two differential outputs of PAs. Indeed, Lattice-type LC Balun works well on the power combination.

However, the problem found is the significant harmonics which would degrade the linearity.

Anyany has experience on the Lattice-type LC Balun? And how to reduce the harmonics especially 2nd & 3rd.

Many thanks in advance.

LC balun is narrow band, so to reduce harmonics of the combined PA's you have to place a Low Pass Filter after the balun.

Thanks very much. Furthermore, any wideband balun?

Try a balun transformer.
Balun