A compact uniform circular array antenna for circularly polarized higher-order OAM beam generation through modes...

Area of Science:

• Electromagnetics and Antennas
• Wireless Communication Technologies

Background:

• Higher-order orbital angular momentum (OAM) beams offer increased data capacity in wireless systems.
• Generating high-order OAM beams typically requires complex antenna arrays and feeding networks.

Purpose of the Study:

• To design and validate a compact uniform circular array (UCA) antenna for generating a sixth-order OAM beam.
• To achieve high-order OAM generation with a reduced number of elements and a simple feeding structure.

Main Methods:

• Utilized mode superposition by combining fifth-order OAM from ring patch elements and first-order OAM from the array.
• Employed a dual-feed configuration with differential feed lengths for a 90-degree phase difference.
• Applied Characteristic Mode Analysis (CMA) to verify the excitation of TM61 modes for OAM radiation.

Main Results:

• Successfully generated a sixth-order OAM beam through mode superposition.
• Achieved circular polarization using sequential element rotation without complex feeding.
• Demonstrated significant mode purity with an axial ratio below 3 dB at 3.55 GHz.

Conclusions:

• The proposed single-layer, low-profile UCA antenna efficiently generates high-order OAM beams.
• The design is suitable for narrowband OAM-based wireless sensor and communication systems.
• This approach reduces the complexity and element count for high-order OAM generation.