Sidelobe suppression in metasurface devices

Abstract

A transceiver system may include first and second metasurfaces, such as radio frequency (RF) metasurfaces or optically reflective tunable liquid crystal metasurfaces (LCMs). In one specific example, a transmit LCM may be tuned by a controller to steerably reflect incident optical radiation at a target transmit steering angle. A laser or other optical radiation source may transmit optical radiation to the transmit LCM at a first angle of incidence. The controller may tune the second tunable LCM to steerably receive optical radiation at a target receive steering angle corresponding to the target transmit steering angle. The received optical radiation may be reflected at a second angle of incidence to a detector.

What is claimed is: 
     
         1 . A method, comprising:
 transmitting, via a radiation source, electromagnetic radiation to a first metasurface at a first angle of incidence with respect to the first metasurface;   steerably reflecting, via the first metasurface, the electromagnetic radiation incident at the first angle of incidence at a transmit steering angle;   steerably receiving, via a second metasurface, electromagnetic radiation at a receive steering angle corresponding to the transmit steering angle; and   detecting, via a detector, the received electromagnetic radiation reflected by the second metasurface from a second angle of incidence with respect to the second metasurface, wherein the first angle of incidence is different than the second angle of incidence.   
     
     
         2 . The method of  claim 1 , wherein the first angle of incidence and the second angle of incidence are selected to offset a dominant sidelobe of the first metasurface with respect to a dominant sidelobe of the second metasurface for each of a plurality of transmit steering angles. 
     
     
         3 . The method of  claim 1 , wherein a difference between the first angle of incidence and the second angle of incidence is selected to generate asymmetric transmit and receive radiation patterns for a given transmit steering angle and corresponding receive steering angle. 
     
     
         4 . The method of  claim 3 , wherein the difference between the first angle of incidence and the second angle of incidence corresponds to one diffraction order of the first and second metasurfaces. 
     
     
         5 . The method of  claim 1 , wherein transmitting electromagnetic radiation to the first metasurface via the radiation source comprises transmitting one of microwave radiation and optical radiation. 
     
     
         6 . The method of  claim 1 , wherein each of the first and second metasurfaces comprises an optically reflective tunable metasurface. 
     
     
         7 . A non-transitory computer-readable medium with instructions stored thereon that, when executed by a processor, operate to:
 tune a first metasurface to steerably transmit radiation incident at a first angle of incidence at a transmit steering angle;   tune a second metasurface to steerably receive radiation at a receive steering angle corresponding to the transmit steering angle; and   detect, via a detector, the radiation received by the second metasurface that is directed to the detector at a second angle of incidence that is different than the first angle of incidence.   
     
     
         8 . The non-transitory computer-readable medium of  claim 7 , wherein each of the first and second metasurfaces comprises an optically reflective tunable metasurface. 
     
     
         9 . The non-transitory computer-readable medium of  claim 7 , wherein the instructions, when executed, further operate to:
 generate an image of an object using the detected radiation.   
     
     
         10 . The non-transitory computer-readable medium of  claim 7 , wherein the instructions, when executed, further operate to:
 decode the detected radiation for electronic communication.   
     
     
         11 . The non-transitory computer-readable medium of  claim 7 , wherein the first angle of incidence and the second angle of incidence are selected to offset a dominant sidelobe of the first metasurface with respect to a dominant sidelobe of the second metasurface for each of a plurality of transmit steering angles. 
     
     
         12 . The non-transitory computer-readable medium of  claim 7 , wherein a difference between the first angle of incidence and the second angle of incidence is selected to generate asymmetric transmit and receive radiation patterns for a given transmit steering angle and corresponding receive steering angle. 
     
     
         13 . The non-transitory computer-readable medium of  claim 12 , wherein the difference between the first angle of incidence and the second angle of incidence corresponds to one diffraction order of the first and second metasurfaces. 
     
     
         14 . The non-transitory computer-readable medium of  claim 7 , wherein transmitting electromagnetic radiation to the first metasurface comprises transmitting microwave radiation. 
     
     
         15 . The non-transitory computer-readable medium of  claim 7 , wherein each of the first and second metasurfaces comprises an optically reflective tunable metasurface. 
     
     
         16 . A method, comprising:
 transmitting, via a laser, optical radiation to a first optically reflective tunable liquid crystal metasurface (LCM) at a first angle of incidence;   tuning the first optically reflective tunable LCM to deflect incident optical radiation at a transmit steering angle;   tuning a second optically reflective tunable LCM to steerably receive optical radiation at a receive steering angle corresponding to the transmit steering angle; and   detecting, via a detector, optical radiation reflected by the second optically reflective tunable LCM from a second angle of incidence with respect to the second tunable metasurface, wherein the first angle of incidence is different than the second angle of incidence.   
     
     
         17 . The method of  claim 16 , wherein a difference between the first angle of incidence and the second angle of incidence corresponds to one diffraction order of the first and second optically reflective tunable LCMs. 
     
     
         18 . The method of  claim 16 , wherein a difference between the first angle of incidence and the second angle of incidence is selected to generate asymmetric transmit and receive radiation patterns for each transmit steering angle and corresponding receive steering angle. 
     
     
         19 . The method of  claim 16 , wherein the first angle of incidence and the second angle of incidence are selected to offset a dominant sidelobe of the first metasurface with respect to a dominant sidelobe of the second metasurface for at least one steering angle. 
     
     
         20 . The method of  claim 16 , wherein the laser emits optical radiation between 850 nanometers and 1550 nanometers.