Improved Performance of 1 × 2 Circular Polarized Antenna Array Design for ISM Band Applications

In this paper, a new single microstrip patch antenna (MPA) design is proposed using the square shape of the radiating element which is rotated by 45 degrees and incorporated by a square slot rotated by 45 degrees. The main goal behind using the slot technique in the center of the patch is to achieve the circular polarization (CP) manner and adapt the input impedance with the port. This single MPA operates at 5.8 GHz in the ISM (industrial, scientific, and medical) band. To improve the gain and directivity of this single MPA, we develop a two-element antenna array by associating two basic patches of the single MPA using the T-junction technique to a single excitation port. This array is effective in terms of a high gain of 7 dBi, high directivity of 7.10 dB, and highest radiation efficiency of about 97.34% at the resonant frequency of 5.8 GHz. In addition, this suggested antenna array operates with a good adaptation with the port of 50 Ω in terms of a reflection coefficient of -27.57 dB, and input impedance of 48.81+3.22j Ω, and it operates with a good CP manner, with an excellent axial ratio of 1.23 dB at 5.8 GHz. The proposed antenna array design is shown to be a viable solution for wireless charging systems in electric vehicles and for powering sensors and communication modules in autonomous vehicles.