The scattering process of waves
by a planar junction of two half-planes, one of which is impedance and
the other a reflectionless metasurface, is studied. The transition
boundary method is considered. The scattered geometric optics field is
obtained by subtracting the initial fields from the total geometric
optics field. The diffracted field is obtained by considering the
relation between diffracted and scattered geometric optics field
expressions in the transition boundary. The ultimate expressions of
the fields are examined numerically for different parameter
groups.