A Miniature Eight-Port Antenna Array Based on Split-Ring Resonators for 5G Sub-6 GHz Handset Applications

Area of Science:

• Electrical Engineering
• Electromagnetics
• Antenna Theory

Background:

• Fifth-generation (5G) mobile communication systems require advanced antenna solutions for sub-6 GHz frequencies.
• Miniaturization and high performance are critical design constraints for handset antennas.

Purpose of the Study:

• To propose a miniature eight-port multiple-input multiple-output (MIMO) antenna array for 5G sub-6 GHz handset applications.
• To achieve wideband operation and high isolation within a compact form factor.

Main Methods:

• Design of a novel antenna element featuring a Chinese character "" shaped radiator and three split-ring resonators (SRR) on a metal frame.
• Analysis of antenna performance including impedance bandwidth, current distribution, and effects of single-handed holding.
• Measurement and calculation of key performance metrics such as total efficiency, isolation, envelope correlation coefficient (ECC), and channel capacity (CC).

Main Results:

• The individual antenna element measures 6.8 × 7 × 1 mm³ (47.6 mm³).
• Achieved a -10 dB impedance bandwidth of 1.7 GHz (3.3-5 GHz), covering 5G NR bands N77, N78, and N79.
• Measured total efficiencies range from 40% to 80%, isolation is better than 12 dB, ECC is less than 0.12, and CC is 35-38 bps/Hz.

Conclusions:

• The proposed miniature eight-port MIMO antenna array is a viable solution for 5G mobile handsets.
• The design demonstrates wideband operation, effective use of the metal frame, and minimized spacing, addressing key requirements for 5G applications.