Polarization Insensitive and Angularly Stable Adaptive Frequency Selective Surface for Automated and on-Demand Electromagnetic Shielding

A new adaptive frequency selective surface (AFSS) has been presented for electromagnetic (EM) shielding applications. Passive EM shields lack reconfigurability which severely limits their application. Moreover, active EM shields involving PIN diodes and other active elements consume power all the time. This paper incorporates a novel adaptive approach with frequency selective surface (FSS) to create a smart environment. The unit cell of the designed FSS has the shape of an octagon loop; each loop includes a pin diode at 180 degrees intervals. An envelope detector has been used to trigger the microcontroller whenever an incident RF signal has been detected. The PIN diodes are switched ON or OFF automatically based on the requirements using a microcontroller to save power. When the PIN diodes are OFF, the FSS is in the shielding mode and when they are ON it is in the transmission mode. A prototype has been built for measurements. A good agreement between theory and experiment has been observed. The proposed AFSS can also be programmed as a time-based event and remote-controlled for on-demand EM wave shielding applications.