Devices and methods for positioning external devices in relation to implanted devices

A method for transferring power and data at an operating frequency, comprising:

• transferring one or both of power and data from an external device to an implantable device,
• wherein the external device comprises a first single turn loop antenna and a backing material configured to guide radiation from the first single turn loop antenna into a body of a patient,
• wherein the implantable device comprises a second single turn loop antenna,
• wherein a first loop of the first single turn loop antenna is larger than a second loop of the second single turn loop antenna, and
• wherein each of a size of the first loop, a size of the second loop, and a separation distance between the first and second loops when the implantable device is implanted within the body is less than ⅕ of a wavelength of the operating frequency of the system.