Nonreciprocity and scan blindness in phased arrays using balanced-fed radiators

It is shown that scanning an array of balanced wire or patch type radiators in their
E
-plane can destroy the radiators' dual probe symmetry. This loss of symmetry can cause the radiator's unit cell "scattering matrix" to be nonreciprocal, where in this scattering matrix each of the radiator's dual probes is now considered as a separate input port. This breaking of radiator symmetry can result in scan blindness when the radiator is fed by a reactive power divider balun. This effect is illustrated by a numerical example using balanced-fed patch radiators.