Ka-band broadband high-gain circularly polarized antenna array with high cross-polarization discrimination

Area of Science:

• Electromagnetics and Wave Propagation
• Antenna Theory and Design
• Microwave Engineering

Background:

• Millimeter-wave antenna arrays face challenges with mutual coupling, impacting performance.
• Achieving broadband circularly polarized signals with high cross-polarization discrimination is crucial for advanced communication systems.

Purpose of the Study:

• To propose and validate a Ka-band broadband circularly polarized antenna array with enhanced cross-polarization discrimination.
• To mitigate mutual coupling issues in millimeter-wave antenna arrays through a novel decoupling structure.

Main Methods:

• Design of a 2x2 sequentially rotated (SR) array of substrate integrated cavity (SIC) magnetoelectric dipole elements.
• Implementation of a double-layer substrate integrated waveguide (SIW) SR feeding network for precise phase control.
• Integration of a multi-layer square-loop array decoupling surface (ADS) to suppress element coupling.

Main Results:

• Achieved 30.33% impedance bandwidth (23.45-32.02 GHz) and 35.52% axial ratio (AR) bandwidth (22.48-32.19 GHz).
• Demonstrated cross-polarization discrimination (XPD) better than 30 dB across the operating band.
• Obtained a peak gain of 12.47 dBic with less than 3 dB variation over a wide frequency range (25.95-33.14 GHz).

Conclusions:

• The proposed antenna array effectively suppresses mutual coupling using the integrated ADS.
• The design offers significant potential for high-performance 5G millimeter-wave communication systems.
• The array exhibits excellent broadband, high XPD, and stable gain characteristics.