Radar antenna array with parasitic elements excited by surface waves

Abstract

An apparatus includes a waveguide of an antenna block configured to propagate electromagnetic energy along a propagation direction. The antenna block includes a port located on a bottom surface of the antenna block and an antenna array located on a top surface of the antenna block. The antenna block further includes a set of waveguides in the antenna block configured to couple the antenna array to the port. Additionally, the antenna block includes at least one surface wave radiator, where the surface wave radiator is located on the top surface of the antenna block.

What is claimed is: 
     
         1 . A vehicle comprising:
 a vehicle radar system having one or more radar units, wherein each radar unit comprises one or more antennas and at least one parasitic surface wave radiator; and   a computing device configured to:
 cause the vehicle radar system transmit radar signals in an environment of the vehicle using the one or more radar units; 
 receive reflection signals corresponding to the radar signals; and 
 generate a map of the environment of the vehicle based on the reflection signals. 
   
     
     
         2 . The vehicle of  claim 1 , wherein each radar unit further comprises:
 an antenna block, wherein the one or more antennas are located on a top surface of the antenna block.   
     
     
         3 . The vehicle of  claim 2 , wherein each radar unit further comprises:
 a port located on the antenna block.   
     
     
         4 . The vehicle of  claim 3 , wherein each radar unit further comprises:
 a waveguide in the antenna block configured to couple the one or more antennas to the port.   
     
     
         5 . The vehicle of  claim 4 , wherein the at least one parasitic surface wave radiator is configured to radiate at least a portion of a surface wave propagating along the top surface of the antenna block. 
     
     
         6 . The vehicle of  claim 5 , wherein the at least one parasitic surface wave radiator comprises a slot or a raised element. 
     
     
         7 . The vehicle of  claim 1 , wherein the at least one parasitic surface wave radiator comprises a plurality of parasitic surface wave radiators, and wherein the plurality of parasitic surface wave radiators are arranged in an array. 
     
     
         8 . The vehicle of  claim 1  wherein the at least one parasitic surface wave radiator comprises a patch. 
     
     
         9 . The vehicle of  claim 1 , wherein the at least one parasitic surface wave radiator comprises a dielectric radiator. 
     
     
         10 . The vehicle of  claim 1 , wherein the at least one parasitic surface wave radiator is configured to steer a radiated beam. 
     
     
         11 . The vehicle of  claim 1 , wherein the computing device is further configured to:
 control the vehicle based on the map of the environment of the vehicle.   
     
     
         12 . A method comprising:
 causing a vehicle radar system to transmit radar signals in an environment of a vehicle using one or more radar units, wherein each radar unit comprises one or more antennas and at least one parasitic surface wave radiator;   receiving, at a computing device, reflection signals corresponding to the radar signals; and   generating a map of the environment based on the reflection signals.   
     
     
         13 . The method of  claim 12 , further comprising:
 causing the vehicle radar system to steer a radiated beam using the at least one parasitic surface wave radiator.   
     
     
         14 . The method of  claim 12 , wherein each radar unit further comprises:
 an antenna block, wherein the one or more antennas are located on a top surface of the antenna block.   
     
     
         15 . The method of  claim 14 , wherein each radar unit further comprises:
 a port located on the antenna block; and   a waveguide in the antenna block configured to couple the one or more antennas to the port.   
     
     
         16 . The method of  claim 15 , wherein the at least one parasitic surface wave radiator is configured to radiate at least a portion of a surface wave propagating along the top surface of the antenna block. 
     
     
         17 . The method of  claim 12 , further comprising:
 controlling the vehicle based on the map of the environment.   
     
     
         18 . A system comprising:
 a vehicle;   a vehicle radar system coupled to the vehicle, wherein the vehicle radar system includes one or more radar units, and wherein each radar unit comprises one or more antennas and at least one parasitic surface wave radiator; and   a computing device configured to:
 cause the vehicle radar system transmit radar signals in an environment of the vehicle using the one or more radar units; 
 receive reflection signals corresponding to the radar signals; and 
 generate a map of the environment of the vehicle based on the reflection signals. 
   
     
     
         19 . The system of  claim 18 , wherein the one or more antennas corresponds to an antenna array arranged in a particular direction; and
 wherein the at least one parasitic surface wave radiator comprises:   a plurality of parasitic surface wave radiators, wherein the plurality of parasitic surface wave radiators comprises a first parasitic surface wave radiator and a second parasitic surface wave radiator arranged on opposite sides parallel to the particular direction.   
     
     
         20 . The system of  claim 18 , wherein the computing device is further configured to:
 control the vehicle based on the map of the environment.