System for Converting Electromagnetic Radiation to Electrical Energy Using Metamaterials

Abstract

Spectral tuning of heat source to emit radiation at a desired frequency or frequency band is accomplished using metamaterials. The metamaterials include a structured geometry having holes with dimensions and spacing chosen such that the resulting surface will emit radiation in the desired spectrum. A collector can be made of a similar metamaterial or antenna array to detect the emitted radiation and transfer it to a converter device that converts the detected radiation to electricity. Embodiments also provide efficient coupling to the converter device for energy harvesting. Cooling of the converter devices can be accomplished using a cooling sink or deep space.

What is claimed is: 
     
         1 . A system for harvesting electricity from electromagnetic radiation, comprising:
 a metamaterial that is heated by a heat source and has a surface that is engineered to exhibit resonance that generates an electric field having an enhanced electric field strength in the presence of frequencies associated with heat; and
 a rectenna having an antenna element and a transfer structure, wherein the rectenna is placed in the enhanced electric field generated over the metamaterial surface and converts energy in the electric field to electricity. 
   
     
     
         2 . The system recited in  claim 1 , wherein the surface of the metamaterial has a plurality of holes over each of which an electric field is concentrated when the metamaterial is heated and wherein a rectenna is placed in the electric field concentrated over one or more of the holes. 
     
     
         3 . The system recited in  claim 2 , wherein the rectenna are placed with 3 μm over one or more of the plurality of holes. 
     
     
         4 . The system recited in  claim 2 , wherein the rectenna are placed within one half the tuned frequency wavelength over one or more of the plurality of holes. 
     
     
         5 . The system recited in  claim 2 , wherein each hole is square with a side length of a, and the tuned frequency ω pl , is determined as: 
       
         
           
             
               
                 ω 
                 
                   p 
                   ⁢ 
                   l 
                 
               
               = 
               
                 
                   π 
                   ⁢ 
                   
                     c 
                     0 
                   
                 
                 
                   a 
                   ⁢ 
                   
                     
                       
                         ɛ 
                         H 
                       
                       ⁢ 
                       
                         μ 
                         H 
                       
                     
                   
                 
               
             
           
         
       
     
     
         6 . The system recited in  claim 2 , wherein each hole is circular has a depth of approximately 40 μm, the spacing between holes is approximately 50 μm, and each hole has a diameter of approximately 10 μm. 
     
     
         7 . The system recited in  claim 2 , wherein each hole is square has a depth of approximately 40 μm, the spacing between holes is approximately 50 μm, and each side has a length of approximately 10 μm. 
     
     
         8 . The system recited in  claim 2 , wherein the distribution of plurality of holes is periodic. 
     
     
         9 . The system recited in  claim 1 , wherein the rectenna are configured to be tuned to 1 THz. 
     
     
         10 . The system recited in  claim 1 , wherein the metamaterial surface is engineered to exhibit a dip in a reflectance spectrum at a frequency associated with heat. 
     
     
         11 . The system recited in  claim 12 , wherein the dip in the reflectance spectrum has a minimized width and a maximised depth. 
     
     
         12 . The system recited in  claim 1 , wherein the components of the system are configured to be manufactured using roll-to-roll technology. 
     
     
         13 . The system recited in  claim 1 , wherein the metamaterial is copper. 
     
     
         14 . The system recited in  claim 1 , wherein the metamaterial has a thickness of 50 μm. 
     
     
         15 . The system recited in  claim 2 , wherein each hole is filled with a highly insulating material that is transparent to radiation. 
     
     
         16 . The system recited in  claim 1 , wherein materials on top of the rectenna couple the rectenna to a cold source. 
     
     
         17 . The system recited in  claim 2 , wherein each hole is filled with a highly insulating material that is transparent to radiation. 
     
     
         18 . The system recited in  claim 1 , wherein the rectenna is surrounded by an insulating material to prevent lost heat from the heat source, and to serve to guide heat via radiation to the rectenna. 
     
     
         19 . The system recited in  claim 1 , further comprising materials on top of the rectenna to conduct heat and couple the rectenna to a cold source,