Compact Size MIMO Amer Fractal Slot Antenna for 3G, LTE (4G), WLAN, WiMAX, ISM and 5G Communications

In this study, an Amer fractal slot antenna is proposed as a multiple input, multiple output (MIMO) antenna with four ports. The antenna is excited by CPW (coplanar waveguide) to control the leakage of electromagnetic energy, which leads to a high match between the antenna and input impedance, thus achieving dual operating bands of 1.5–19.2 GHz and 25–37.2 GHz for port 1, dual operating bands of 1.4–19 GHz and 20–35.5 GHz for port 2, a wide operating band of 1.4–29 GHz for port 3, and dual operating bands of 1.6–21 GHz and 22–37 GHz for port 4. Therefore, the proposed antenna meets all the market needs of wireless communication technologies such as 3G, Long Term Evolution (LTE, 2.6 GHz /3.5 GHz), Wireless Local Area Network (WLAN, 2.4 GHz/5 GHz), Worldwide Interoperability for Microwave Access (WiMAX, 2.5 GHz/3.5 GHz/5 GHz), Industrial, Scientific and Medical (ISM, 2.4 GHz/ 5 GHz), and 5G (5–6 GHz and 27–28 GHz). The proposed antenna can be used as dual opposite ports for the frequency range 1.5–15 GHz and as four-element MIMO arrays for frequencies of 15–30 GHz. The MIMO fractal antenna has circular polarization characteristics with axial ratio bandwidths (ARBWs) of 4.7–5.8 GHz for port 1, 2.5–2.6 GHz and 5.4–6.5 GHz for the port 2, 4–5.9 GHz for port 3, and 5.5–10 GHz for port 4. Due to its compact size (33 mm $\times33$ mm $\times0.8$ mm), low profile, and acceptable values of gain and efficiency, the proposed antenna is suitable for many portable wireless communication devices.