A CPW-Fed Circular SRR-Inspired Flexible Antenna Using Polydimethylsiloxane (PDMS) Substrate for WLAN and WBAN Applications

This article presents a <inline-formula> <tex-math notation="LaTeX">$50\times40$ </tex-math></inline-formula> mm² coplanar waveguide (CPW)-fed triple-band flexible antenna operating at 5, 5.8, and 6.6 GHz for wireless local area network (WLAN) and wireless body area network (WBAN) applications. In the proposed design, polydimethylsiloxane (PDMS) is used as a substrate with a dielectric constant <inline-formula> <tex-math notation="LaTeX">$\varepsilon _{r}$ </tex-math></inline-formula> of 2.65 and a loss tangent tan<inline-formula> <tex-math notation="LaTeX">$\delta _{\varepsilon r}$ </tex-math></inline-formula> of 0.02. In addition to the rectangular slot on the ground, the presented antenna has a single circular split-ring resonator (SRR) structure on the same side of the patch. This provides the required frequency notched characteristics for the targeted frequency bands, compactness, minimize losses, and backward radiation when used in close proximity to the human body. The proposed flexible antenna provides stable results in terms of performance parameters and specific absorption rate (SAR). We have also investigated the antenna under different operating conditions of moisture and bending. There exists a strong correlation between the simulation and measured findings.