A Miniaturized Modified-L Antenna with Dual Bands for Energy-Saving Internet of Things Applications

Compact L-shaped antenna designs that are suited for energy-efficient Internet of Things (IoT) applications are compared and integrated in this paper. A tiny single-band L-shaped antenna operating at the 2.4 GHz ISM band and a miniaturized dual-band modified-L antenna supporting both the 2.4 GHz and sub- $\text{GHz}(860-930 \text{MHz})$ bands are two innovative antenna shapes that are investigated. Both antennas use microstrip feeding techniques and are made on inexpensive FR4 substrates. Important improvements include omnidirectional radiation patterns, enhanced impedance matching ($\mathrm{S} 11<-10 \text{dB}$), bent-stub loading and slotted partial ground planes, which allow dual-resonance behavior. Peak increases of $2.4-2.8 \text{dBi}$ and efficiency of 80 % are confirmed by HFSS simulations. Comparing the suggested antennas to conventional L-shaped designs, it is shown that they enhance bandwidth by up to 25 % and reduce footprint by 10 %. Wearable health monitoring devices, smart agriculture and industrial monitoring systems that use protocols like LoRa, ZigBee and Wi-Fi are examples of application domains. By combining knowledge from earlier research on multiband, wideband and miniaturized antenna technologies [1]–[20], the study offers a scalable and space-efficient solution for nextgeneration IoT installations. In the future, energy-harvesting and reconfigurability modules will be integrated to further improve antenna flexibility in dynamic wireless situations.