Midfield coupler

Abstract

Described herein are devices, systems, and methods for wireless power transfer utilizing a midfield source and implant. In one variation, a midfield source may be realized by a patterned metal plate composed of one of more subwavelength structures. These midfield sources may manipulate evanescent fields outside a material (e.g., tissue) to excite and control propagating fields inside the material (e.g., tissue) and thereby generate spatially confined and adaptive energy transport in the material (e.g., tissue). The energy may be received by an implanted device, which may be configured for one or more functions such as stimulation, sensing, or drug delivery.

1 - 20 . (canceled) 
     
     
         21 . A system comprising:
 an external powering device comprising:
 a first radio transceiver configured to transmit and receive microwave signals at a first frequency, 
 a midfield coupler electrically coupled to the radio transceiver, the midfield coupler including a substrate and a midfield plate on the substrate, the midfield plate including one or more slot antennas formed therein; and 
   an at least partially implantable biocompatible device configured to receive power from the external powering device, the implantable device comprising:
 an outer casing; 
 a second radio transceiver encased by the outer casing, the second radio transceiver configured to receive microwave signals at the first frequency, 
 an antenna, the antenna electrically coupled to the second radio transceiver, the antenna encased by the outer casing, 
 an encapsulant encapsulating the antenna and the second radio transceiver, the encapsulant between the antenna and the outer casing and between the second radio transceiver and the outer casing, the encapsulant made of a dielectric material with a dielectric permittivity between a dielectric permittivity of animal tissue and a dielectric permittivity of the substrate, and 
 at least one surface electrode exposed on the outer casing. 
   
     
     
         22 . The system of  claim 21 , wherein the dielectric material includes a high dielectric, low loss material. 
     
     
         23 . The system of  claim 21 , wherein the midfield coupler is configured to convert electrical signals from the radio transmitter to signals with a non-negligible H-field component parallel to a surface of the midfield coupler and focus the converted signals to a location within tissue that is within a wavelength, as measured in air, of the microwave signals. 
     
     
         24 . The system of  claim 21 , wherein the outer casing includes at least one of polyurethane, silicone, ceramics, nylon, polycarbonate, Acrylonitrile butadiene styrene (ABS), a urethane blend, thermoplastic, and epoxy. 
     
     
         25 . The system of  claim 24 , wherein the outer casing includes a thermoplastic. 
     
     
         26 . The system of  claim 21 , wherein the antenna resides on a planar surface. 
     
     
         27 . The system of  claim 26 , wherein the antenna includes two straight, thin conductors. 
     
     
         28 . The system of  claim 27 , wherein the implantable device is a substantially straight tube having a length substantially greater than a cross-section. 
     
     
         29 . A system comprising:
 a radio transmitter configured to transmit microwave signals, the radio transmitter including a midfield coupler including a substrate and a midfield plate on the substrate, the midfield plate including one or more slot antennas formed therein; and   an at least partially implantable biocompatible device comprising:
 an outer casing; 
 a radio receiver within the outer casing, 
 an antenna within the outer casing and configured to receive electrical signals, the antenna electrically coupled to the radio receiver, and 
 an encapsulant, within the outer casing, encapsulating the antenna, the encapsulant made of a dielectric material with a dielectric permittivity between a dielectric permittivity of animal tissue and a dielectric permittivity of the substrate. 
   
     
     
         30 . The system of  claim 29 , wherein the dielectric material includes a high dielectric, low loss material. 
     
     
         31 . The system of  claim 29 , wherein the encapsulant further encapsulates circuitry, including the radio receiver, of the at least partially implantable biocompatible device. 
     
     
         32 . The system of  claim 29 , wherein the midfield coupler is configured to convert electrical signals from the radio transmitter to signals with a non-negligible H-field component parallel to a surface of the midfield coupler and focuses the converted signals to a location within tissue that is within a wavelength, as measured in air, of the microwave signals. 
     
     
         33 . The system of  claim 29 , wherein the outer casing includes at least one of polyurethane, silicone, ceramic, nylon, polycarbonate, acrylonitrile butadiene styrene (ABS), a urethane blend, thermoplastic, and epoxy. 
     
     
         34 . The system of  claim 33 , wherein the outer casing includes thermoplastic. 
     
     
         35 . An at least partially implantable, biocompatible apparatus comprising:
 an outer casing;   a radio configured to transmit and receive microwave signals, the radio encased by the outer casing;   an antenna electrically coupled to the radio and encased by the outer casing; and   an encapsulant within the outer casing, the encapsulant surrounding the radio and the antenna and the encapsulant including a dielectric permittivity between a dielectric permittivity of animal tissue and a dielectric permittivity of a substrate of a midfield coupler.   
     
     
         36 . The apparatus of  claim 35 , wherein the antenna is an electric field based antenna. 
     
     
         37 . The apparatus of  claim 36 , wherein the antenna is a dipole antenna. 
     
     
         38 . The apparatus of  claim 35 , further comprising one or more surface electrodes exposed on the outer casing and electrically coupled to the radio. 
     
     
         39 . The apparatus of  claim 35 , wherein the encapsulant includes a high dielectric, low loss material. 
     
     
         40 . The apparatus of  claim 35 , wherein the outer casing includes at least one of polyurethane, silicone, ceramic, nylon, a urethane blend, polycarbonate, acrylonitrile butadiene styrene (ABS), thermoplastic, and epoxy.