Channel-Enhanced Transmission–Reflection Switchable Reconfigurable Intelligent Surface With Arbitrary Source and Terminal Positions

This article introduces a reconfigurable intelligent surface (RIS) engineered to enhance communication channels regardless of the source and terminal positions. The unit can switch between reflection and transmission modes, dynamically manipulating the entire electromagnetic environment. Central to this feature is the transmit antenna of unit, which uses diodes alternates between symmetric (reflective) and asymmetric (radiated) structures. To ensure a consistent operating frequency in both modes, their operating current patterns differ in a new nested patch. A $16\times 16$ RIS was fabricated to measure the far-field patterns and channel characteristics with the source and terminal arbitrarily relative to the RIS. Results show that the RIS can switch between transmission and reflection modes and enhance the communication channel in various situations. The proposed RIS may have applications to adjust electromagnetic distribution in multispace and enhance wireless communication. Finally, we discuss a possible design for transforming this RIS into a reflection-absorbing switchable one.