Investigating the S-parameter (|S₁₁|) of CPW-fed antenna using four different dielectric substrate materials for RF multiband applications

This article aims to examine the |S₁₁| parameter of a multiband Coplanar Waveguide (CPW)-fed antenna. The proposed square-shaped antenna-1 (Ant.1) and antenna-2 (Ant. 2) are primarily composed of three ground terminal stubs: Terminal-1 (T1), Terminal-2 (T2), and Terminal-3 (T3), all of which have an inverted L-shaped radiating patch. The proposed antennas' resonance frequencies (f_r) can be adjusted by the electrical dimension and length of the stub resonators, the dielectric constant (ε_r) of substrate materials, and their appropriate thicknesses. It will have an impact on their return loss (|S₁₁|), Impedance Bandwidth (IBW), radiation pattern, and antenna performance in terms of frequency characteristics, as demonstrated in this article. The proposed structure based on Flame-Retardant fiber glass epoxy (FR4) substrate covered a wideband frequency range from 1.5 to 3.2 GHz, (IBW = 1.7 GHz) and from 3.4 to 3.65 GHz (IBW = 0.25 GHz). The total IBW is 1.95 GHz, at S₁₁ ≤ −10 dB with three resonance frequencies of values f_r1 = 1.75, f_r2 = 2.65, and f_r3 = 3.50 GHz) for triple-band applications. The results are compared with the research work reported earlier. The proposed Ant.1 ensured, dual and triple band applications whereas the proposed Ant. 2 ensured dual, triple and quad bands applications with reasonable antennas' sizes similar to the earlier reported works. Furthermore, the impacts of various substrate materials as well as different lengths of multi-stub resonators on the operating bands and resonance frequency are thoroughly explored and analyzed for these antennas.