Circularly Polarized Array Antenna Using the Sequential Rotation Network Feeding for X-Band Communication

This paper presents a novel Circularly Polarized (CP) microstrip array antenna with circular shape and slotted by an elliptical ring for X-band communication. This array antenna consists of 4 paths. Each patch is designed with a unique model, and the purposed antenna is mainly circular-shaped. An elliptical ring slot is set at the center of the circular-shaped patch. And a pair of triangle shapes employed as truncation factor is placed at the edge of the circular-shaped antenna. This microstrip array antenna is developed by 2 × 2 patches in a sequential rotation mode with relative phases 0˚, 90˚, 180˚ and 270˚. Total dimension of this array antenna is 60.92 mm × 60.92 mm. The simulated result shows a good agreement with minimum requirement. The center frequency of the antenna design is 8.2 GHz with low-frequency at 8 GHz and high frequency at 8.4 GHz. The proposed antenna produced under -10 dB S11 of 21.9%, maximum gain of 12.47 dBic at the center frequency, and axial ratio bandwidth obtained 12.2%. Simulated result has been validated by fabrication and measurement, then the structure of the antenna design is fabricated on NPC-H22A with a thickness of 1.6 mm and dielectric constant of 2.17. Complete investigation and experimentation are presented in the next sections.