A dual circularly polarized flower-shaped antenna for WiFi-6E basestation communications with low sidelobe level and high gain

This paper proposes a dual circularly polarized (CP) flower-shaped antenna with low sidelobe levels and high gain for WiFi-6E basestation communications. The antenna consists of two printed circuit board (PCB) substrates and a polyvinyl chloride (PVC) radome, and is excited by a pair of coaxial cables. Initially, a flower-shaped parasitic patch etched with slots is placed atop a square main radiated patch that is directly fed by two orthogonal “L”-shaped microstrip lines with constant amplitude in phase, achieving wideband, high gain, and dual CP characteristics. Furthermore, a three-level T-junction power divider network collaborates in conjunction with a dual-port electrical bridge to excite an array that is comprised of the proposed 4×4 antenna elements to achieve higher array gain. Finally, an open box-shaped PVC radome is selected for fixation and protection, contributing significantly to sidelobe level (SLL) reduction. The working mechanisms including precise phase control and SLL reduction, etc., are analyzed using equivalent circuit and E-field distribution, among other methods. Measured results demonstrate excellent performances, such as a low profile of 0.074 λ 0 ( λ 0 is the free-space wavelength at the starting frequency), a low SLL of less than -14.4 dB, a wide impedance bandwidth of 20% (5.85-7.15 GHz), a wide axial ratio (AR) bandwidth of 21% (5.83-7.4 GHz), a peak gain of larger than 19.4 dBic in left hand circular polarization (LHCP), another peak gain of better than 19.6 dBic in right hand circular polarization (RHCP), and a high radiation efficiency of larger than 72%. 1. Design Principles: • Dual Circular Polarization : Enables simultaneous reception of left- and right-handed signals, enhancing performance in multipath environments. • Flower-Shaped Structure : Promotes uniform radiation, reduces sidelobe levels, and improves directivity and efficiency. 2. Impact on WiFi-6E Communication: • High Gain : Expands signal coverage, optimizing communication between base stations and remote devices. • Low Sidelobe Levels : Suppresses interference and enhances signal clarity and stability. • Improved Connectivity : Increases compatibility with various polarization modes, enhancing connectivity in dense networks.