Multiband microstrip MIMO antenna with CSRR loaded for GSM and LTE applications

A multiband multiple-input multiple-output (MIMO) microstrip patch antenna using complementary split-ring resonator (CSRR) structure is proposed for Global System for Mobile (GSM) and Long-Term Evolution (LTE) applications. The proposed antenna consists of two radiating patches with folded microstrip lines and symmetric L-shaped slots, which are connected together with an isolation line for reducing the coupling effect between ports. CSSRs are used to enhance the isolation and to control resonant frequencies. Radiation elements of the antenna are designed for various applications such as GSM (900 MHz) and LTE (1900/2300/2600 MHz). The proposed antenna is fed by 50 omega CPW lines. Various parameters calculated in this antenna show a return loss and an isolation of less than -10 dB and -15 dB respectively. Moreover, the gain of 2.8dBi and the radiation efficiency of 72% have been obtained for proposed antenna. The presented antenna occupying 60 x 70 x 0.8 mm(3) is implemented on an FR4 substrate.