A Circularly Polarized High-Gain Planar 2 × 2 Dipole-Array Antenna Fed by a 4-Way Gysel Power Divider for WLAN Applications

Abstract

In this letter, a circularly polarized high-gain planar 2 × 2 dipole-array antenna for wireless local area networks, radio frequency identification, radar, and satellite communication applications is proposed. The proposed array antenna consists of four planar dipole antennas with integrated microstrip-to-parallel-stripline linear tapered balun and feeding network. The designed array antenna is fed by a modified 4-way Gysel power divider. The proposed antenna uses three stacked metal layers, and a metal reflector under the antenna boosts the overall antenna gain. The size of the designed antenna on 3.2 mm thick FR4 substrate was 150 mm × 150 mm × 20 mm including the reflector. The designed antenna had left-hand circular polarization (LHCP), and its measured LHCP gain value was 8.70–9.62 dBic at 2.4–2.6 GHz band. The measured axial ratio was 0.3–2.2 dB at the same frequency band of interest. A thorough theoretical analysis and design equations of the proposed array antenna are presented in this letter.