A compact triband microstrip antenna suitable for internet of things (IoT) and wearable sensing applications is presented in this work. The antenna is implemented on a low-cost FR4 substrate and incorporates a stacked configuration consisting of an inset-fed rectangular patch, rectangular slots, parasitic elements, and a foam superstrate layer supporting a split ring resonator. The sequential modification of the radiating structure enables the generation of multiple resonant modes while maintaining compact antenna dimensions of \(38.95 \times 34.7\) mm \(^{2}\) . The proposed antenna operates at three resonant frequencies located at 4.33 GHz, 4.96 GHz, and 6.1 GHz, with reflection coefficients below \(-\,10\) dB across the desired operating bands. The corresponding impedance bandwidths are 4.21–− 4.37 GHz, 4.93–− 4.98 GHz, and 6.02–− 6.27 GHz. To evaluate its suitability for wearable communication systems, specific absorption rate (SAR) analysis was conducted using a multilayer human body phantom model consisting of skin, fat, and muscle tissues. Using standard printed circuit board fabrication techniques, a prototype of the antenna was manufactured and experimentally tested in the microwave engineering laboratory. The low-profile, simple structure, and low-cost substrate of the antenna make it appropriate for integration in IoT sensor nodes, wearable monitoring devices, body area networks and portable wireless sensing systems. Hence, the proposed design offers a feasible and efficient solution to multiband wireless communication in miniaturized IoT and wearable platforms.
