Dual band complementary split-ring resonator-loaded printed dipole antenna arrays for pattern diversity multiple-input-multiple-output applications

In this study, a dual-band multiple-input-multiple-output (MIMO) antenna with pattern diversity is designed, targeting at the 2.4 GHz wireless local area network and 1.8 GHz global system of mobile communication application bands. The proposed scheme utilises arrays of printed dipoles fed with signals of equal amplitude but different input-phase values to achieve diverse radiation patterns in the operating frequency bands. The printed dipoles are loaded with complementary split-ring resonators to obtain one additional lower-frequency resonance, ensuring simultaneous miniaturisation and dual-band characteristics. The impedance, radiation and diversity performances of the proposed MIMO configuration are analysed by full-wave simulations in ANSYS high-frequency structure simulator. It is observed that both the antennas in the MIMO configuration cover the common frequency range of 1.7-1.8 and 2.25-2.5 GHz, with satisfactory average gain and stable radiation pattern in the working bands. Experimental results on the fabricated structure are in good agreement with simulation results, confirming validity of the proposed concept.