AUT Journal of Electrical Engineering

AUT Journal of Electrical Engineering

Design of a Hexagonal Stepped Impedance Resonator Textile Antenna for Robust Biomedical and Environmental Monitoring

Document Type : Research Article

Authors
Yeddu Eswar Vasanth Kumar 1
Gurindapalli Rajita 2
Kokilagadda Phaninder Vinay 3
1 M.Tech, (Ph.D), GIET University, Gunupur, Odisha, India
2 Ph.D, Dr. G. Rajita, GIET University, Gunupur, Odisha, India
3 Ph.D, Dr. K. P. Vinay, RAGHU Engineering College, Vskp, A.P, India
10.22060/eej.2026.25097.5837
Abstract
This work presents a compact, hexagon-shaped wideband antenna designed for wearable applications in the Industrial, Scientific, and Medical band. The antenna is fabricated on a flexible felt substrate with a dielectric constant of 1.22 and a loss tangent of 0.016, achieving a compact footprint of 35 × 30 × 2 mm³. A Coplanar Waveguide feed integrated with a Stepped Impedance Resonator is employed to enhance impedance matching and bandwidth performance. The felt substrate exhibits excellent mechanical durability and electromagnetic stability under repeated bending and typical wear conditions, ensuring reliable long-term operation. The proposed antenna achieves a peak gain of 7.31 dB at 5.82 GHz and maintains a Specific Absorption Rate of 1.08 W/kg for 1 g of tissue, which is well within regulatory safety limits. Beyond communication, the antenna demonstrates moisture-sensing capability, exhibiting a consistent downward shift in resonant frequency with increasing substrate humidity. While stable under bending, excessive moisture leads to detuning and impedance mismatch. The strong correlation between simulated and measured results validates the proposed design as a robust and multifunctional solution for wearable biomedical and ultra-wideband sensing applications.
Keywords
CPW
ISM
SIR
Textile Fabric
Wearable Medical Device
Subjects
AUT Journal of Electrical Engineering
Volume 58, Issue 3
Summer 2026
Pages 645-662