Ultra-Compact 4-Port MIMO Antenna with Defected Ground Structure and SAR Analysis for 28/38 GHz 5G Mobile Devices

Abstract

To tackle the challenge of keeping 5G mobile devices compact while supporting millimeter-wave bands, we've created an ultra-compact 4-port dual-band MIMO antenna with a defected ground structure (DGS). This design minimizes mutual coupling and covers a broad frequency range. Built on a Rogers TMM4 substrate with dimensions of 17.76×17.76 mm², the antenna includes four planar patch antennas positioned perpendicularly at the corners. Each antenna operates at 28/38 GHz and features a rectangular patch with four rectangular slots and a full ground plane. The patches are separated by 0.5 λo, with the DGS further reducing mutual coupling. Both simulations and measurements indicate a significant reduction in mutual coupling (−39 to −60 dB), improving ECC, TARC, MEG, and DG. Time-domain and SAR analyses confirm the antenna's efficiency and its suitability for 5G devices.

KEYWORDS:

• Defected ground structure (DGS)
• millimeter-wave
• 4-port
• multiple-input multiple-output (MIMO)
• mutual coupling (MC)
• 5G
• mobile devices
• equivalent circuit model

Acknowledgments

The authors express their gratitude to the New Damietta Higher Institute of Engineering and Technology (NDETI), Damietta, Egypt, as well as the University Teknikal Malaysia Melaka (UTeM) and the Ministry of Higher Education (MOHE) of Malaysia for their support in this project.

Disclosure statement

No potential conflict of interest was reported by the author(s).