High-efficiency ferrite meander antenna (HEMA) for LTE applications

This paper presents a high-efficiency ferrite meander antenna (HEMA), which can be used to realize a 2 × 2 multiple-input-multiple-output (MIMO) communication system when it is used both at the transmitter and the receiver end. This antenna is designed to operate at 2.45 GHz center frequency (f_c). It consists of two spatially separated half-cycle microstrip meander structures. Instead of using ferrite material for the entire substrate, it is used only beneath each meander structure. A standard FR-4 substrate is used as a system board. Impedance bandwidth and the radiation patterns of the fabricated antenna are measured and compared with those of the simulation results. The -10 dB impedance bandwidth of the fabricated antenna is 262 MHz, whereas the simulated bandwidth is 235 MHz. According to the simulations, the gain and the efficiency of the antenna are 2.2 dB and 81%, respectively. The efficiency of the antenna is confirmed by measurements. By using the simulated radiation patterns, correlation between the radiation patterns is calculated and used in generating the channel matrix. Mutual impedance of the antennas and the antenna efficiency are also included in the channel matrix, which in turn is used in bit error rate (BER) and ergodic capacity simulations. BER and ergodic capacity are used as performance metrics. The effect of antenna efficiency, mutual impedance of the antennas, and correlation between radiation patterns on system performance are presented.