Simulation-Based Investigation of Locally Available Natural Materials as Dielectric Substrates for Microstrip Patch Antennas

Abstract: This research presents a simulation-based performance investigation of a 5.8 GHz microstrip patch antenna using locally available natural materials as dielectric substrates. Natural substrates, including Bamboo, Wood, Paper, Cotton and Palm fiber, were characterized alongside standard FR-4 dielectric material. The analytical framework evaluated fundamental dielectric parameters, including relative permittivity (εr), loss tangent (tan δ), imaginary permittivity (ε″) and effective permittivity (εeff), revealing an inverse relationship between εr and required patch footprint (ranging from 15.798 mm × 11.803 mm for FR-4 up to 22.683 mm × 19.139 mm for Cotton). Closed-form transmission line equations produced an initial analytical frequency offset of 9.58% to 12.28% above the 5.8 GHz target, necessitating numerical co-optimization in CST Studio Suite. Benchmark validation of custom FR-4 (εr = 4.36, tan δ = 0.01) against CST’s built-in library model confirmed numerical model fidelity across 4–7 GHz. Full-wave CST simulations demonstrated that Cotton (εr = 1.6, tan δ = 0.0015) achieved superior performance with the highest radiation efficiency (67.0%) and peak gain (3.66 dBi), outperforming all other natural dielectrics. Wood and Palm fiber provided strong impedance matching (S11 = −35.31 dB and −33.36 dB; VSWR = 1.35 and 1.13) with moderate efficiencies (45.8% and 41.2%). Paper exhibited the highest attenuation (tan δ = 0.04), yielding the lowest radiation efficiency (29.8%) and peak gain (1.45 dBi). These findings establish the viability of natural dielectrics for eco-friendly wireless systems while delineating key physical trade-offs in substrate loss and antenna geometry.

Keywords: Microstrip patch antenna, Natural dielectric substrate, 5.8 GHz ISM band,CST Studio Suite,Radiation efficiency, Eco-friendly antenna