Apparatus and methods are described, including a stent configured to be placed in a lumen. The stent includes a generally cylindrical stent body including a plurality of struts, at least one electrode post protruding from the stent body, and a plurality of antenna posts protruding longitudinally from an end of the stent body. The antenna posts are longitudinally separated from the electrode post. An antenna is disposed annularly on the antenna posts, such that the antenna posts separate the antenna from the end of the stent body, and at least one electrode is coupled to the stent by being placed on the electrode post. Additional embodiments are also described.