A Bandwidth- and Gain-Enhanced Microstrip Patch Antenna Using TM30-Like Mode and λg/4 Resonator Feeding

This paper presents a bandwidth- and gain-enhanced microstrip patch antenna operating at 3.5 GHz for 5G applications. The proposed design integrates a λg/4 resonator-based feeding structure with TM30-like mode operation, enabling a dual-resonance mechanism that improves impedance bandwidth without increasing structural complexity. This approach provides a simple single-layer solution for achieving high gain and low sidelobe levels. Simulated results show a bandwidth of 4.0% (3.41-3.55 GHz) and a peak realized gain of 12.8 dBi at 3.52 GHz. Reflection-coefficient measurements confirm the impedance behavior, yielding a bandwidth of 3.7% (3.41-3.54 GHz).