A four-element antenna array for MIMO-LTE systems

Summary form only given. In this paper presents a compact MIMO array platform to operate at 2.6GHz Long Term Evolution (LTE) band for wireless communication systems. The array consists of four compact patch antennas on a dielectric substrate with total dimensions of 125×62.5×1.27mm³. Modifications of the ground plane along with systematic placement and orientation of each antenna on top of the substrate plays a key role to reduce the mutual coupling which normally degrades the MIMO arrays performance. The modifications of the ground plane, placement, and orientation of each antenna on the array was done based on the insights provided by the theory of CM. The CM-based approach considers the chassis as a fundamental structure, and by examining the set of characteristic currents in the PCB/dielectric substrate, allows the designer to define the position of each antenna of the MIMO array.The performance of this MIMO array has been evaluated through simulations and measurements of the scattering parameters and radiation patterns. The isolation obtained is over 25dB between all the antennas, and the maximum achieved gain of a single antenna is 3.14dBi with other antennas terminated with appropriate loads (50-ohms). One metric that provides very important information about the performance of the array for MIMO systems is the correlation. This enveloped correlation coefficient between signals received by the antennas of the array can be computed through the S-parameters with the assumption that the incoming signals are uniformly distributed, i.e. the direction of arrival of each multipath component has equal probability. The results of the correlation coefficients calculated through the measured S-parameters are much less than 0.000015 at 2.6Ghz; these very low values can potentially enable the generation of more independent and parallel subchannels producing high performance wireless communication systems with MIMO arrays.