Radar absorption structures made of an active frequency selective surfaces (AFSS) have enormous potential in the aviation, naval, and other industries. In this research paper, a systematic review (SR) is carried out in the field of the AFSS to bring uncertainties, obstacles, challenges, classifications, applications, and design issues that arrive in the development of the sub-6 GHz architecture. To bias the AFSS component, as per the signal requirements, a unique set of circuits (PIN diode) is required, with ON and OFF state and a transmission zone. The bandwidth of which is determined by the bias voltage supplied. It can behave as a complicated hybrid impedance structure by providing ON and OFF biasing voltage to a PIN diode embodied in an FSS structure. Higher manufacturing costs of AFSS components, more significant complexities involved, a large amount of power consumption, and reactive impedance losses are some common limitations faced while implementing and designing an AFSS. Many envisioned problems are corrected with the AFSS design, current or creative implementations, and processing parameters are investigated progressively. It implies that new AFSSs will be an alternative to regular FSSs in the future. This paper is based on Kitchenham’s three-phase review procedure and supplements it with results, views, and recommendations from other leading experts in the field.

In this paper, a dual concentric square-loop dual-polarized reconfigurable frequency selective surface with a high tuning ratio of 2.02 operating in the 1.53–3.10 GHz band is proposed. This high tuning ratio has been achieved by using four SMV1430-LF varactor diodes, which have been actuated using a simple biasing arrangement made of stubs and four metallic vias per unit-cell. The unit-cell has been rigorously analyzed, and an equivalent circuit (EC) model has been developed for the physical insight. The proposed EC model also demonstrates the reconfigurability of the unit-cell and thus predicts its behavior. The effect of the angular incidence of the impinging electromagnetic wave on the structure up to a 45º has been experimentally verified, which demonstrates its angular stability and polarization insensitive behavior. The structure may find applications in the electromagnetic spectrum’s L, S , and 2.45 GHz ISM bands.