Compact and Wideband U-Slotted Microstrip Antenna for Modern IoT Devices at ISM Band

This paper presents the design and analysis of a compact U-slotted microstrip patch antenna with a truncated feed, optimized for IoT applications. The antenna is realized on an FR4 substrate with a thickness of 1.6 mm, offering a low-cost and mechanically stable platform. The proposed design achieves a wide operational bandwidth ranging from 1.8 GHz to 3.2 GHz, corresponding to a fractional bandwidth of up to 40%, making it suitable for multiple wireless standards such as Wi-Fi, Zigbee, and Bluetooth. Detailed simulations are performed to evaluate the antenna’s performance, including reflection coefficient (S11), voltage standing wave ratio (VSWR), input impedance, radiation pattern, and gain. Results demonstrate efficient impedance matching, stable omnidirectional radiation, and satisfactory gain across the operating band. The integration of the U-slot with the truncated feed enhances multi-resonant behavior while maintaining a compact footprint, making the antenna suitable for smart home devices, wearable sensors, and industrial IoT systems. The proposed antenna design provides a reliable, wideband, and low-profile solution, addressing the size and performance constraints inherent in IoT device integration.