Broadband Circularly Polarized Slot Antenna Loaded by a Multiple-Circular-Sector Patch

Area of Science:

• Electrical Engineering
• Electromagnetics
• Antenna Theory

Background:

• Circularly polarized (CP) antennas are crucial for mitigating polarization mismatch losses in wireless systems.
• Broadband CP antennas are highly sought after for applications requiring stable signal transmission across a wide frequency range.

Purpose of the Study:

• To design and validate a microstrip-fed broadband circularly polarized (CP) slot antenna.
• To enhance the axial ratio (AR) bandwidth through innovative loading techniques.

Main Methods:

• A microstrip-fed slot antenna was designed and fabricated.
• An S-shaped strip was embedded to achieve CP operation.
• A multiple-circular-sector patch was employed as a loading element to broaden the 3 dB axial ratio (AR) bandwidth.

Main Results:

• The fabricated antenna prototype measured 54 mm × 54 mm × 0.8 mm.
• Achieved a -10 dB reflection bandwidth of 81.06% (1.68–3.97 GHz).
• Demonstrated a 3 dB AR bandwidth of 70.55% (1.89–3.95 GHz) with a peak gain of 3.81 dBic.

Conclusions:

• The proposed antenna design effectively achieves broadband CP operation.
• The integration of the S-shaped strip and multi-circular-sector patch significantly enhances the AR bandwidth.
• The experimental results validate the antenna's performance for potential wireless applications.