A Mechanically Rollable Reflectarray With Beam-Scanning Capabilities

Abstract

A novel 1-D beam-steerable reflectarray antenna (RA) is proposed for the Ku-band. The RA aperture consists of 24×48 variable size square patch elements printed on a flexible plastic substrate. The aperture is wrapped around two cylinders to create a 12λ × 12λ illumination window at the operating frequency of 14 GHz. Beam-steering is achieved by mechanically rolling the aperture. To mitigate antenna pattern degradation, an aperture phase distribution optimization technique is presented. The performance of this RA system is studied analytically using array theory. The effects of aperture size and unit-cell size are also discussed. The performance of the proposed RA is validated using simulations and measurements. The results illustrate that our design achieves 1-D beam-steering from-21° to +21° in the elevation plane while maintaining towards the broadside direction a maximum realized gain of 25.1 dBi. In this beam-scanning range, the gain variation is less than 1.5 dB, beamwidth variation is less than 1.6°, and the side lobe level is maintained below-15 dB. In summary, the main advantage of our design is its ability to steer its high gain beam without using complicated feed networks or complex mechanical systems. Such antennas are especially needed in SmallSat and space applications.