A circular polarized reflectarray antenna with electronically steerable beam and interchangeable polarizations

Abstract

The purpose of this paper is the design of a novel single layer reflectarray antenna in X-band, which can electronically steer the antenna beam and change its polarization. Each antenna element includes a circular patch and rings around it, equipped with two varactor diodes, which are positioned perpendicular together to create a circular polarization. First, using these elements, a circular polarized active electromagnetic band-gap (EBG) reflector is implemented. Then, a special feed is placed in a proper distance with respect to EBG reflector and a circular polarized reflectarray antenna is designed, which has capability of switching electronically between right- and left-handed circular polarizations. An electronic active board is designed and fabricated to provide the biasing voltages, control signals, and indicators. The elements of the reflectarray are designed and arranged in such a way that the varactor diodes can be biased independently. Consequently, a 3D beam is created, which can steer up to ±40o. For evaluating the antenna performance, the radiation patterns and the axial ratio of the antenna are determined at the operational frequency of 11.4 GHz. It is illustrated that, increasing the steering angle in θ direction decreases the directivity and the gain of the reflectarray antenna.

Programmable Beam-Steering Capabilities Based on Graphene Plasmonic THz MIMO Antenna via Reconfigurable Intelligent Surfaces (RIS) for IoT Applications

“…The beam scanning or beam forming types are widely studied in the last few years, due to their critical role in phased array systems. The reconfigurable property of the antenna can be implemented by different techniques of electrical or mechanical switches such as p-i-n diodes, varactor diodes, and micro-electromechanical system switches (MEMS) [14,18]. Unfortunately, these types of switches cannot be used in the microscale of the THz spectrum.…”