Scattering Matrix of a Reciprocal, Lossless, and Symmetrical Three-Port Power Divider

This letter provides the analytical expression of the scattering matrix of an arbitrary loss-less reciprocal three-port junction with a plane of symmetry. The 3
$\times $
3 matrix is given in terms of two arbitrary real angles,
$\vartheta $
and
$\varphi $
. Experimental evidence of this fact is also included.