Design and Analysis of Rectangular Circularly Polarized Array Antenna for Flexible IoT Applications

In this work, a Coaxial fed 2 × 2 array antenna is proposed. This antenna employsfour patch elements, and the individual feedlines are connected to a standard coaxial feed. The size of the antenna is 74.4 × 74.4 mm^2 with a substrate thickness of 1.6 mm. Polyamide is used as a substrate which has a dielectric constant of 4.3. The antenna's operating band starts from 4.05 to 4.32 GHz, with a bandwidth of 0.27 GHz and a resonating frequency of 4.2 GHz and 5.2 GHz. The proposed antenna achieved a peak gain of 9.1 dB and a radiation efficiency of 85