An antenna assembly can be configured for RF communications. The antenna assembly can include a ground plane disposed on a substrate. The antenna assembly can include a patch antenna structure spaced apart from the ground plane. The antenna assembly can include one or more grounded posts coupled to and extending from the substrate. The one or more grounded posts can be arranged along at least a portion of a periphery of the patch antenna structure. The patch antenna structure can emit a radiation pattern based at least in part on a transmit signal. The radiation pattern can induce a resultant field in the one or more grounded posts to adjust a characteristic of the radiation pattern.