An antenna assembly includes: a wearable antenna including a conductive signal layer having a radiating surface; a feed conductive layer; and an insulating layer in between the conductive signal layer and the feed conductive layer, and wherein the conductive signal layer, the feed conductive layer, and the insulating layer are fabric-based, wherein the wearable antenna is shaped and sized to be embedded in a subject's clothing with sufficient flexibility to be stretched and bent as the subject implanted with a passive implantable stimulator device maintains routine daily activities, and wherein the wearable antenna is electrically tuned and configured to have the radiating surface of the conductive signal layer facing the subject's skin and a feed point of the feed conductive layer connecting to a controller such that the wearable antenna is non-inductively coupled to the implanted passive stimulator device to supply power the passive implantable stimulator device wirelessly and non-inductively.