A medical device includes an antenna external to a case, package, or encapsulant for the electronic systems of the medical device. In one embodiment, a diabetes infusion pump is enclosed within a metal case, the pump including a processor and a communication module for wireless communications. An antenna is disposed in the delivery tubing of the pump outside the case with an antenna feed interconnecting the external antenna with the internal communication module. In another aspect, a thin film antenna is formed on the outer surface of the case in which a physiological parameter sensor, such as a glucose sensor, is enclosed. Multiple antennas may be used for communications on different frequencies.