Bandwidth and Stability of Reflection Amplifiers for Intelligent Reflecting Surfaces

Intelligent reflecting surfaces have gained significant attention in modern wireless communication systems. This study investigates the stability and bandwidth characteristics of reflection amplifiers based on the current-inverting negative-impedance converters that promise the enhancement of the intelligent reflecting surfaces with unique power amplification capability. Both lumped and distributed network configurations are explored, with derived closed-form necessary stability conditions. Transient simulations validate the proposed criteria, demonstrating the amplifier’s consistent stability. By thought-fully constraining operational bandwidth, the amplifier achieves targeted signal amplification within the desired frequency range, effectively managing reflections beyond this range. These findings hold promise for optimizing IRS efficiency, overcoming passive structure losses, and elevating gain in wireless communication contexts.