Active Multifunctional Frequency Selective Surfaces: An Insight Into Design, Behavior Analysis, and Applications

This investigation provides a critical review of the design methodologies for multifunctional active frequency selective surfaces (MAFSSs) and reconfigurable frequency selective surfaces (RFSSs), collectively referred to as active multifunctional frequency selective surfaces (AMFSSs). The advanced AMFSS structures plays a crucial role in electromagnetic shielding, wireless communication systems, and stealth technology. The review systematically examines the fundamental performance parameters of AMFSS. These parameters include absorption, transmission, reflection, fractional bandwidth (FBW), insertion loss, absorptivity, polarization stability, and angular stability. The design techniques explored, include the integration of active elements (PIN and varactor diodes). Additionally, the incorporation of lumped components (resistors, inductors, and capacitors), the implementation of multilayer architectures, and the utilization of distributed elements (slots and stubs). These techniques facilitate dynamic switching between operational states, enhancing the adaptability and overall performance of AMFSS. Furthermore, a detailed comparative analysis of AMFSS performance metrics—encompassing absorption, transmission, and reflection bandwidths, along with their respective frequency ranges, FBW, polarization characteristics, and angular stability—is presented, offering valuable insights into their practical applications and future advancements.