A Low Profile Circularly Polarized Beam Scanning Patch Array Fed by Parallel Plate Waveguide.

A low-cost, low-profile circularly polarized beam scanning patch array is presented. The patch array is fed by the coupling slots of parallel plate waveguide (PPW), which is excited by a substrate integrated waveguide-based plane wave line source generator. By suggesting a new impedance match method, the coupling slots and truncated patch array are combined for circularly polarized radiation. The beam scanning capability is achieved by the variable inclination method. In the PPW guiding wave layer, a circular plate is cut and separated from the main body of the PPW to make it rotatable around its axis. By rotating the assembly of the circular plate and the above patch layer, the phase difference between the adjacent radiation elements could be controlled. Thus, the circularly polarized beam scanning is realized. A Ku-band prototype array is fabricated and measured to verify the design. The measured peak gain is 19.6 dBi and the scanning range is ±40°, in which range the gain variation is below 2.7 dB and the axial ratio is less than 2.8 dB. [ABSTRACT FROM AUTHOR]