Abstract: A system that includes a power transmitting antenna (124) with a coiled conductor defined by a first axis and a second axis perpendicular to the first axis, where a single plane comprises the first axis and the second axis. The system includes a support layer (140, 142) comprising: a substantially planar top surface and a substantially planar bottom surface opposite the substantially planar top surface arranged parallel to the plane. The support layer also comprises a material with a predetermined resiliency. The support layer is configured to support a mass of a user and maintain a predetermined spacing between the plane of the power transmitting antenna and the user during compression of the material from the mass of the user.

Abstract: This disclosure describes devices, systems, and techniques for recharging power sources using RF energy received by one or more antennae. In one example, an implantable medical device includes a rechargeable power supply and an antenna configured to receive radio frequency (RF) energy having one or more frequencies within at least one of a first range from 1 MHz to 20 MHz or a second range from 100 MHz to 700 MHz. The implantable medical device may also include charging circuitry configured to convert the RF energy to a direct current (DC) power and charge the rechargeable power supply with the DC power.