Design of Six Port Antenna With Frequency Diversity and Diverse Radiation Pattern

Abstract

Based on shared U-shaped patch, a six port antenna with frequency and radiation pattern diversity is investigated in this paper. Two evolutionary U-shaped patches are cascaded together to form a three port antenna with a common ground. Three probes located at the two ends and the middle of the U-shaped patch are used to provide excitation with different phases. In order to improve the impedance bandwidth of each port, both T-shaped and rectangular stubs are loaded on the ground plane. When different ports are excited, the vector currents on the U-shaped patch and the T-shaped stubs show diametrically opposite flow directions, resulting in the diversity of the antenna in frequency and radiation pattern. Two three port antennas form a six port antenna with a relatively compact distance of $0.23\lambda $ . The measured results show that the frequency diversity is specifically manifested as when port 1, 3, 4, 6 are excited respectively, the six port antenna operates in 4.73-5.02 GHz with a peak gain of 5.38 dBi. And, when port 2, 5 are separately excited, the antenna works at 3.80-4.40 GHz with a peak gain of 5.01 dBi. Meanwhile, the six port antenna exhibits diverse radiation patterns with better total efficiency up to 84.8%. Furthermore, the port isolation in the two operating bandwidth is better than 21.7 dB and 18.5 dB, which also indicates that the designed six port antenna can be applied for 5G.

Keywords

• U-shaped patch
• frequency diversity
• diverse radiation patterns
• port isolation
• fifth-generation (5G)