Embodiments of the present invention include a patch antenna having a patch element, a ground plane, a feedline, and an electromagnetic shield. The patch element transmitting and/or receives electromagnetic signals. The ground plane is spaced at a specified distance from the patch element. The feedline guides the electromagnetic signal and extends through an opening in the ground plane and to the patch element. The feedline is electrically coupled to the patch element to guide an electromagnetic signal to or from the patch element. The electromagnetic shield extends, at least partially, between the ground plane and the patch element and is electrically coupled to the ground plane. The electromagnetic shield is configured to control an impedance associated with the feedline between the ground plane and the patch element.