Compact Four-Port MIMO Antenna Using Dual-Polarized Patch and Defected Ground Structure for IoT Devices

Area of Science:

• Electrical Engineering
• Antenna Theory
• Wireless Communications

Background:

• Internet-of-Things (IoT) devices require increasingly compact antennas.
• Scaling traditional single-polarized antennas for multi-port operation leads to larger sizes.
• High channel capacity in IoT necessitates multi-port antenna systems like MIMO.

Purpose of the Study:

• To develop a compact four-port multiple-input multiple-output (MIMO) antenna for IoT applications.
• To achieve multi-port operation and high channel capacity in a reduced antenna footprint.
• To minimize mutual coupling between antenna elements for improved isolation.

Main Methods:

• Utilized a dual-polarized radiator instead of single-polarized elements to reduce size.
• Incorporated an I-shaped defected ground structure (DGS) to mitigate mutual coupling.
• Designed and measured a four-port MIMO antenna with specific dimensions at 5.5 GHz.

Main Results:

• Achieved a compact antenna size of 0.92 λ× 0.73 λ× 0.03 λ at 5.5 GHz.
• Obtained an operating bandwidth of approximately 2.2%.
• Demonstrated isolation better than 20 dB and a peak gain exceeding 6.0 dBi.

Conclusions:

• The proposed dual-polarized radiator and DGS approach enables compact, high-performance MIMO antennas for IoT.
• The design effectively reduces mutual coupling, enhancing isolation between ports.
• The method is scalable and applicable to larger MIMO arrays for future wireless systems.