A new approach to circularly polarized dipole array antenna with polarization conversion technique

Area of Science:

• Electromagnetics and Antenna Theory
• Microwave Engineering
• Wireless Communication Systems

Background:

• Printed dipole array antennas are crucial for modern wireless applications.
• Achieving wide bandwidth and high polarization purity simultaneously remains a design challenge.
• Existing designs often compromise on size or performance for specific frequency bands.

Purpose of the Study:

• To develop a compact circularly polarized printed dipole array antenna (CP-PDA).
• To enhance bandwidth and polarization purity using fractal-inspired elements and parasitic structures.
• To validate the design's performance for various wireless communication standards.

Main Methods:

• Utilized fractal-inspired dipole arms composed of stacked ellipses to increase effective electrical length and bandwidth.
• Incorporated stair-shaped parasitic elements to facilitate linear-to-circular polarization conversion.
• Implemented a sequentially rotated feeding network with Wilkinson power dividers and phase shifters for precise phasing.
• Fabricated prototype antennas on FR4 and Rogers RO4003 substrates using standard PCB etching.

Main Results:

• Achieved a wide impedance bandwidth of 41.12% (1.99-3.02 GHz) and axial ratio bandwidth of 35.02% (2.12-3.02 GHz).
• Demonstrated high polarization purity exceeding 27 dB with right-handed circular polarization (RHCP).
• Obtained a peak gain of 14.16 dBic at 2.55 GHz, consistent with simulation results.
• Confirmed robust performance under practical fabrication tolerances.

Conclusions:

• The proposed CP-PDA effectively integrates fractal geometry and parasitic elements for enhanced performance.
• The antenna's wide bandwidth and high polarization purity make it suitable for WLAN, ISM, and satellite applications.
• The design offers a practical solution for systems requiring resilience to polarization mismatch and multipath fading.