A Metasurface-Based Wearable Bandpass Filter in Ism and Iot Bands for Wearable Applications

The work introduces a metasurface-based (MSbased) one layered slot type dual bandpass filter operating in the microwave <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{S}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{C}$</tex> bands; more specifically in the ISM and IoT bands. The structure is found out to be flexible and compact in nature. The cell dimension of the structure is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.25 \lambda_{0} \times 0.25 \lambda_{0}$</tex>, having a substrate thickness of 0.5 mm. The design comprises of 2 slots; viz one outer rectangular ring-shaped slot and one circular polygon shaped slot, both of which are responsible for bringing the dual-bandpass response in the operating frequency range. More specifically, the proposed structure provides two distinct transmission bands at 2.4 GHz and 4.8 GHz respectively. Additionally, one stop-band has also been realized at 3.9 GHz; thereby making the structure suitable for wearable antenna applications. The electric field distributions have also been carried out; thereby revealing the roles of each of the slots in bring the dual-band response. The low-profile, along with the compact design makes the structure suitable for being a wearable spatial filter. All the simulations of and analyses have been performed and analysed using ANSYS HFSS v2024.