Abstract: The crosspolarization components radiated by adjacent orthogonally linearly polarized feed horns of a reflector antenna system are compensated by structural modifications incorporated in the feed horns. In a first embodiment, the modified feed horns have curved walls and included shaped septa. Other embodiments involve the use of shaped walls or shaped septa only. In the case of an offset reflector, asymmetric modifications of the wall shape and septa are employed. For flared feed horns with rectangular cross section, the crosspolarization compensation is provided by curving the forward edges of the horn walls convexly or concavely as required.