A process device wireless adapter includes a wireless communications module, a metallic housing, and an antenna. The wireless communications module is configured to communicatively couple to a process device and to a wireless receiver. The metallic housing surrounds the wireless communication module and has a first end and a second end. The first end is configured to attach to the process device. In one embodiment, a metallic shield contacts the housing second end such that the metallic shield and the housing form a substantially continuous conductive surface. The antenna is communicatively coupled to the wireless communication module and separated from the wireless communication module by the metallic shield. Preferably, the wireless communications module illustratively includes a printed circuit board that has a length that is greater than its width.