Design of Tri-Band Patch Antenna with Enhanced Bandwidth and Diversity Pattern for Indoor Wireless Communication

A novel tri-band patch antenna with enhanced bandwidth and a diverse radiation pattern is presented in this study. An off-center probe is introduced to excite a conventional circular patch antenna, and the multi-frequency resonance modes of TM01, TM02, and TM03 with different radiation properties are obtained. Four metal cambered strips are distributed around the circular patch to adjust the impedance matching of the circular patch antenna. In order to widen the impedance bandwidth, a parasitic patch placed above the circular patch antenna is employed in this work. Then, a double-layer patch antenna is manufactured and tested to verify the accuracy of the theoretical analysis and simulated result. The measured results, which are basically consistent with the simulated results, show that the designed antenna can operate in three bandwidths of 1.79–1.81 GHz, 3.74–4.0 GHz, and 4.93–5.44 GHz, with radiation patterns of directional, omnidirectional, and three-beam pointing. The radiation efficiency higher than 85.6% and the maximum gain greater than 9.42 dBi suggest that the investigated antenna is suitable for multi-service scenarios in wireless communication.