170° Circular Sector Microstrip Antenna for GSM‐IoT Application: A Better Alternative of Classical Circular Patch

Abstract

In the current wireless era, where advanced wireless services (AWS‐2) like the Internet of Things (IoT) with handheld devices are a major focus, the exploration and low‐cost design of printed planar antennas is crucial. Circular sector microstrip antennas (CSMA) are ideal in this context, offering better performance than the conventional circular microstrip antenna (CCMA) despite their smaller size. However, selecting optimal parameters for CSMA remains a challenge due to the lack of established theory and design guidelines. This study presents a thorough, methodical analysis and outlines comprehensive design guidelines, aiding future designers in determining optimal configurations for specific GSM‐IoT applications. Unlike earlier intuition‐driven, simulation‐based designs, this study presents the final CSMA design through quantitative analysis and compact design guidelines. Among various sector angles, the 170° CSMA stands out, offering better performance than the classical circular microstrip antenna despite a 55% reduction in aperture area. This paper proposes the 170° CSMA as a superior alternative to CCMA, enabling miniaturization with significantly improved polarization purity and good gain. The fabricated prototype was experimentally verified and compared to CCMA. The proposed CSMA achieves better gain, efficiency, and polarization purity compared to CCMA at the same operating frequency (1.87 GHz for GSM IoT applications). © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.