A technique for improving impedance matching in a phased array antenna involves placing a segmented fence around the antenna elements of the array. The antenna elements are arranged above a ground surface such as a ground plane. The segmented fence includes spaced-apart conductive projections electrically coupled to and extending from the ground surface, such that the segmented fence partially terminates electric fields traveling in directions parallel to the ground surface. The segmented fence lies in paths extending in at least two directions along the ground surface to define fence enclosures that surround individual antenna elements. With dual-polarization or multi-polarization dipole antenna elements, the fence enclosures partially terminate the electric field in each direction parallel to the ground surface to simplify impedance matching without unduly restricting the magnetic field.