Generally discussed herein are systems, devices, and methods for providing a therapy (e.g., stimulation) and/or data signal using an implantable device. Systems, devices and methods for interacting with (e.g., communicating with, receiving power from) an external device are also provided. A system can include an external power source that propagates a field within tissue and an at least partially implantable device configured to receive the propagated field from the external power source, the implantable device including circuitry, a first antenna electrically coupled to the circuitry, a second antenna electrically coupled to the first antenna, and an electrode electrically connected to the circuitry.