CompactMIMOantenna using stepped impedance resonator-based metasurface for5GandWIFIapplications

A compact metasurface-based multiple-input and multiple-output (MIMO) antenna using the stepped impedance resonator (SIR) for 5G and WIFI applications is investigated in this article. The SIR patch unit-cells are periodically etched on the two sides of a thin PCB substrate. As a result, the metal-insulator-metal (MIM) capacitor as the series left-hand (LH) capacitor is introduced into the right-handed transmission line (RH-TL). Besides, the RH inductor could be easily adjusted through the SIR patch. Based on the dispersion relation of the metamaterial-inspired SIR TL, a compact metasurface antenna is proposed and analyzed. A 3-cell MIMO antenna with a reduced oversize of 0.48 lambda 0 x 1.34 lambda 0 x 0.05 lambda(0)(with lambda(0)being the free-wavelength at 4.7 GHz.) for WIFI application is proposed and fabricated. Good agreement between measurement and simulation has been observed. Wide impedance bandwidth (covering 4.68-5.75 GHz, 20.5%) and good isolation (all below -25 dB) are achieved. The measured peak gain and radiation efficiency are greater than 7.8 dBi and 90%, respectively. Owing to a compact antenna configuration, wide bandwidth (covering both 5G sub-6GHz and WIFI bands), good radiation performance, and an easy fabrication process, this antenna is well suited for 5G or/and 5 GHz WIFI application in the base station.