Adaptive Array Design using Least Mean Square Algorithm

Abstract

 Abstract: This paper presents the designing and testing of an 8-element linear array for Adaptive Antenna applications using the Least Mean Square (LMS) algorithm towards improving the directive gain of the array. A conventional patch antenna is optimized to operate at 2.35 GHz (4G applications) and this design is extended up to 8 elements using CST Microwave Studio parameterization. The S-parameters, Return Loss, Gain and VSWR of the antenna array are studied for the 2, 4, and 8 elements adaptive array. The simulation results are validated on the hardware setup and found closely matching with the experimental results. The resulting eight-element antenna array geometry is optimized with a coaxial feeding technique. This geometry appears promising in improving the gain from 6.13 to 23.5 dBi for a single element to eight elements respectively. Further, the LMS algorithm is used to compute the optimal complex weights considering different angles for desired User (60 o and 30 o ) and Interferer (10 o and 15 o ) during MATLAB simulation and then these optimal weights are fed to antenna elements using CST for beam steering in a different direction.Maximas are obtained at 54 o and 28 o when nulls are at 10 o and 15 o using CST software which is closely matching with MATLAB results.