Two closely spaced microstrip patches with high isolation for full-duplex/MIMO applications

Area of Science:

• Electrical Engineering
• Electromagnetics
• Antenna Theory

Background:

• Closely spaced antennas suffer from poor isolation, limiting performance in full-duplex and MIMO systems.
• High mutual coupling between antenna ports causes signal interference and degrades system efficiency.

Purpose of the Study:

• To propose and validate an effective method for significantly enhancing the isolation of closely spaced two-port patch antennas.
• To enable practical deployment of these antennas in full-duplex transceivers and MIMO systems.

Main Methods:

• Utilizing an E-plane configuration with two rectangular microstrip patches.
• Introducing a grounded stub strategically placed between the radiating patches to suppress mutual coupling.
• Fabricating and measuring an antenna prototype to validate the proposed concept.

Main Results:

• Achieved port-to-port mutual coupling suppression down to -50 dB.
• Demonstrated a significant isolation enhancement of 43 dB compared to a coupled design.
• Confirmed good MIMO diversity performance with low envelope correlation coefficient and high diversity gain.

Conclusions:

• The proposed grounded stub method effectively enhances antenna isolation for closely spaced patch antennas.
• The developed antenna is suitable for self-interference cancellation in full-duplex communication systems.
• The antenna exhibits favorable characteristics for MIMO applications, ensuring reliable wireless communication.