Multiband circularly polarized microstrip patch antenna with Minkowski fractal slot for wireless communications

A multiband circularly polarized microstrip patch antenna including a Minkowski fractal slot for wireless communication applications in the frequency bands 1.39 GHz, 2.45 GHz (WLAN band), 3.48 GHz (Mobile Wi-Max), 5.8 GHz (U-NII high-band), and 6.29 GHz has been proposed. The proposed antenna consists of two substrates mounted on top of the ground plane. The antenna has been fed with a 50 Ω microstripline which is etched on top of the lower substrate. The second iteration Minkowski fractal slot is etched on a truncated square patch which is on top of the upper substrate. The substrate has a size of 80 mm × 82 mm × 1.6 mm. The measured results show that the proposed antenna could excite for five resonant bands of 1.35 GHz, 2.45 GHz, 3.5 GHz, 5.8 GHz, and 6.25 GHz, and has reflection coefficients of −15 dB for 1.35 GHz, −16 dB for 2.45 GHz, −22 dB for 3.5 GHz, −23 dB for 5.8 GHz, and −13 dB for 6.25 GHz as well as an axial ratio bandwidth of 3.42 GHz–3.47 GHz. The maximum gains of the antenna are 5.92 dBi for 1.39 GHz, 6.15 dBi for 2.45 GHz, 8.36 dBi for 3.48 GHz, 9.64 dBi for 5.8 GHz, and 6.69 dBi for 6.29 GHz. The simulations and optimizations have been carried through Computer Simulation Technology Microwave Studio (CST-MWS) software. © 2021, Electromagnetics Academy. All rights reserved.