A highly compact Fabry Perot cavity-based MIMO antenna with decorrelated fields

Area of Science:

• Electromagnetics
• Antenna Theory
• Microwave Engineering

Background:

• Multiple-input-multiple-output (MIMO) antennas offer improved spectral efficiency and link reliability.
• Closely spaced antenna elements in MIMO systems often suffer from high correlation, degrading performance.
• Existing methods to reduce correlation may require larger antenna profiles or specific element placements.

Purpose of the Study:

• To design a low-profile Fabry-Perot cavity-based MIMO antenna with a minimized correlation coefficient.
• To investigate the effectiveness of a phase-gradient partially reflective surface (PRS) in decorrelating closely placed antenna elements.
• To achieve significant correlation reduction at a sub-wavelength height.

Main Methods:

• Design of a Fabry-Perot cavity incorporating a phase-gradient PRS.
• Tailoring the PRS reflection phase to be complementary to the ground plane's phase.
• Placement of the PRS at a height of λ/10 above the antenna elements.
• Simulation and analysis of the correlation coefficient reduction.

Main Results:

• The proposed PRS effectively tilts the fields of closely placed antenna elements.
• A significant reduction in the correlation coefficient, approaching 95%, was achieved.
• The decorrelation was realized at a remarkably low height of λ/10, substantially less than conventional λ/4.

Conclusions:

• The designed low-profile Fabry-Perot cavity antenna with PRS offers a viable solution for reducing MIMO correlation.
• The complementary phase design of the PRS is crucial for effective field decorrelation.
• This approach enables compact MIMO antenna designs with enhanced performance characteristics.