Beam scanning antenna and method of beam scanning
The present disclosure provides a low-cost beam scanning antenna and method of beam scanning in which two phase shifts are performed in an array of antenna elements. One of the phase shifts is performed in discrete stepwise increments in a feedline of the antenna element and another phase shift is performed by radiating a signal through variable phase shifters. The amount of phase shift provided by the variable phase shifters is varied by changing a rotation angle of the variable phase shifters.
1. A beam scanning antenna, comprising:
at least one linear array element, each linear array element having
at least one patch antenna, each patch antenna including
a feed line,
a radiating element configured to radiate a signal from the feed line,
a phase shifting device configured to provide a first phase shift in the feed line, and
a precision rotary device; and
at least one metasurface-based superstrate positioned above the respective patch antenna and configured to introduce a second phase shift in the signal traversing therethrough;
wherein the second phase shift varies due to rotation of the at least one metasurface-based superstrate by the precision rotary device.
2. The beam scanning antenna of claim 1 , wherein the first phase shift is a stepwise increment of θ x degrees, and the second phase shift is a range of 0 to θ x degrees.
3. The beam scanning antenna of claim 2 , wherein θ x =45 degrees.
4. The beam scanning antenna of claim 1 , wherein the at least one metasurface-based superstrate is of a truncated periodic structure.
5. The beam scanning antenna of claim 1 , wherein the phase shifting device is a plurality of switches.
6. The beam scanning antenna of claim 1 , wherein the phase shifting device is a plurality of liquid crystal layers.
7. The beam scanning antenna of claim 1 , wherein the at least one metasurface-based superstrate has a circular contour.
8. The beam scanning antenna of claim 1 , wherein the precision rotary device is a stepper motor.