  We relate bulk fields in Randall-Sundrum AdS_5 phenomenological models to the
world-volume fields of probe D7 branes in the Klebanov-Witten background of
type IIB string theory. The string constructions are described by AdS_5 X
T^{1,1} in their near-horizon geometry, with T^{1,1} a 5d compact internal
manifold that yields N=1 supersymmetry in the dual 4d gauge theory. The
effective 5d Lagrangian description derived from the explicit string
construction leads to additional features that are not usually encountered in
phenomenological model building.
