Wideband, Beam-Steerable Reflectarray Antennas Exploiting Electronically Reconfigurable Polarization-Rotating Phase Shifters

We present a wideband reflectarray antenna with electronic beam-steering capability. The beam-steerable reflectarray uses an electronically reconfigurable polarization-rotating unit cell (PRUC) that acts as a wideband 1 bit phase shifter. The unit cell consists of four metallic single-headed arrows placed above a ground plane. The four arrows are connected to the unit cell's bottom surface, which contains two p-i-n diodes for switching and three lumped inductors for RF-DC isolation. Changing the bias states of the two antiparallel p-i-n diodes reconfigures the unit cell between two operating states that provide a +90 degrees and -90 degrees polarization rotation (PR). Simulation results for the unit cell show a wide frequency range of 8.5-11.5 GHz over which the reconfigurable unit cell provides dominant reflection coefficients of >-2 dB and relative phase shifts of 0 degrees and 180 degrees for the two operating states. The proposed unit cell was used to construct a 256-element, fully electronically reconfigurable reflectarray prototype with aperture dimensions of 192 mm x 192 mm to demonstrate the design concept. The digital control circuitry needed to individually control the unit cells was also designed and fabricated. Experimental characterization of the reconfigurable reflectarray demonstrated the 2-D beam scanning capability within the scan range of +/- 60 degrees over a 30% bandwidth.

Automated summary

We propose a wideband reflectarray antenna with electronic beam-steering capability. The reflectarray uses an electronically reconfigurable polarization-rotating unit cell to achieve beam-steering. We construct a prototype with 256 elements to demonstrate the effectiveness of the design concept.