Comparison of Conformal and Planar CPW-Fed Circularly Polarized UWB Square Slot Antennas for WLAN, WiMAX, and 5G Applications

摘要

In this article, a compact circular-polarized CPW-fed square slot antenna conformed on the cylindrical structure is designed to suit for WiFi, WiMAX, and 5G applications. The antenna is designed to resonate in the frequency band of 2- 4.5 GHz, thus covering all major frequency bands of IEEE 802.11 (2.4-2.48 GHz), IEEE 802.16 (2.5-2.69GHz/3.4-3.69 GHz), and 5G (3.3-3.69 GHz), with acceptable gain and radiation patterns for the above applications. Obtained 3-dB axial ratio bandwidth is in the range of 2.95-4.20 GHz. The antenna is designed using semi-flexible RT/duroid substrate having a dielectric constant ε_r = 2.2 with a loss tangent of tan δ = 0.0009. The proposed antennas consist of F-shaped feeding structure and L-shaped strip line connected to the square-ring ground plane. Initially, planar version of antenna is simulated with FR4 and RT/duroid substrate materials, and compared the performance of these two antennas in terms of impedance bandwidth, axial ratio, radiation patterns, and gain. Secondly, RT/duroid material is considered for conformal structure, and its performance is compared for various cylindrical curvatures. From the simulation results, the conformal antenna with different radii has achieved almost similar performance metrics, except a slight variation in the axial ratio and radiation patterns. The proposed antennas are designed and simulated on ANSYS HFSS 16.1 software.