Mitigation of mutual coupling effects in microstrip adaptive arrays for portable devices

In the last decade, antenna and sensor array processing has attracted considerable interest in the signal processing community, and has been applied to a variety of areas ranging from biomedical applications to telecommunication networks. In telecommunication, the importance of antenna array processing initiates from its ability to cancel the noise and interfering signals, mitigate the multipath and fading due to the environment effects, reduce the total power consumption, and its ability to replace the mechanical scanning arrays. The objective of this work is to improve the performance of adaptive array systems by taking the inter-element coupling effects into account. Many publications discussed the adaptive arrays techniques neglecting the coupling effects, but in practical antennas the elements of the array affect each other through mutual coupling and this reduces the adaptive antenna system performance. In the present work the adaptive array response is considered in two cases, beamforming and Direction of Arrival [DOA] estimation algorithms. To be able to compensate the coupling effects the coupling needs to be calculated. Here, the coupling in Uniform Linear Array (ULA) of MicroStrip (MS) patches is calculated using two Matlab codes and FEKO software based on MOM technique. This small array composed of three MS elements, is considered as a replacement of the single element mobile station antenna. The final numerical simulations for the proposed adaptive array system prove that including coupling effects greatly improve performance of the array.