Varactor Controlled X-Band Passive RIS Optimization.

Reconfigurable intelligent surface (RIS) is one of the possible solutions to overcome challenges that bring up the 6G communication networks. Unit cell design for RIS is similar in many aspects to the design of artificial magnetic conductors (AMC) because both have a common nature of changing the phase of the reflected wave. However, RIS is aimed at controlling the angle of reflection to maintain requirements for the radiation pattern similar to phased antenna arrays such as low side lobes and beamwidth. The paper reviews the criteria for optimizing RIS: unit cell dimensions, phase span, frequency bandwidth, and loss. An optimization algorithm is proposed for the proper accounting of RIS optimization criteria. A new X-band unit cell is designed using the proposed optimization algorithm. [ABSTRACT FROM AUTHOR]