A New Compact, Stable, and Dual-Band Active Frequency Selective Surface with Closely Spaced Resonances for Wireless Applications at 2.4 and 2.9 GHz

This paper presents a dual-band active frequency selective surface (AFSS) with closely spaced bands and angular stability for wireless applications at 2.4 and 2.9 GHz. The proposed AFSS element geometry is composed of a slotted cross dipole combined with four ring patches, where the diameter of the ring patches at the top of the geometry is 1.618 times greater than the diameter of the ones at the bottom. The choice of this multiplying factor, used to define the geometry of the proposed patch element, is based on the Fibonacci sequence of numbers. In addition, to perform frequency reconfiguration, two p-i-n diode switches are used, which are placed at the input of the ring patches placed at the top of the AFSS element geometry. The AFSS simulation is performed using Ansoft HFSS software and using generalization of the WCIP, i.e., GWCIP, method. The simulated results are compared with the experimental ones for validation purpose. A very good agreement is observed between the simulated and measured results.