An ultra‐miniaturized single‐layer multiband frequency selective surface with vent for wireless communication

Summary A novel single‐layer ultra‐miniaturized multi‐band Frequency Selective Surface (FSS) with a circular vent is designed for shielding LTE and ISM bands. The top layer of the proposed FSS unit cell incorporates a circular patch along with convoluted arms. The designed FSS unit cell exhibits band‐rejection characteristics with a resonance of 800 MHz, 2.45 GHz, and 5 GHz and bandwidths of 523 MHz, 687 MHz, and 725 MHz, respectively. The periodicity of an ultra‐miniaturized FSS unit cell is 0.024λօ x 0.024λօ, encompassing a spatial vent hole of 0.01λօ, where λօ corresponds to the lowest operating frequency. Moreover, the proposed FSS unit cell remains unaltered angular stability up to 75° with less than 1% frequency deviation in TE and TM modes. Good polarization insensitivity for the designed four‐fold symmetrical FSS unit cell is achieved. Further, an Equivalent Circuit Model (ECM) analysis is developed to infer the physical insight of the proposed FSS unit cell. The FSS prototype is measured for the assertion, and the good agreement between the findings from simulation and measurement is validated. For real‐time assertion, the FSS prototype is verified using the Amitech SDR04. Thus, FSS is a promising candidate with good ventilation for shielding the LTE, Bluetooth, and Wi‐Fi application bands. The work presents the ultra‐miniaturized multi‐band Frequency Selective Surface with a vent hole for shielding wireless communication bands such as LTE, Bluetooth, and Wi‐Fi applications. It operates as a spatial filter at 800 MHz, 2.45 GHz, and 5 GHz with a 10 dB bandwidth of 523 MHz, 687 MHz, and 725 MHz, respectively. The FSS, with an ultra‐miniaturized footprint of 0.024λօ along with a vent of 0.01λօ, exhibits a high angular stability of 75օ for transverse electric (TE) and transverse magnetic (TM) modes.