A MIMO Antenna Utilizing Modified Apollonian Fractal for Sub-6 5G Wireless Applications

Abstract

In this paper, a quad-element multiple-input multiple-output (MIMO) antenna is designed using a modified Apollonian fractal shape for 5G Wireless communication. The proposed antenna comprises four radiating Apollonian fractal elements placed at optimal positions, along with a bottom layer incorporating a segmented ground plane. Each radiating element is composed of a microstrip feed with a quarter-wave transformer to improve impedance matching. The proposed Apollonian fractal-shaped MIMO antenna operates over the frequency range of 3.3–3.8 GHz, achieving an impedance bandwidth where S11 is less than -10 dB and mutual coupling below -20 dB. The envelope correlation coefficient (ECC) remains below 0.05, ensuring excellent diversity performance. Furthermore, the performance parameters of the Apollonian fractal- shaped MIMO antenna are evaluated based on S-parameters, such as the envelope correlation coefficient and channel capacity. Experimental measurements show that the ECC is lower than 0.05, while the channel capacity loss is below 0.6, reflecting reasonable agreement with the simulation results.