Analysis and Design of Compact Antenna Arrays

Abstract

This thesis presents and discusses novel design and analysis techniques of compact antenna arrays. A practical design of a bifilar helical compact antenna array with a substantial size reduction capability is demonstrated with both theoretical and measurement results. For transmitting compact antenna arrays, a novel method is introduced for decoupling the radiation patterns of the arrays elements, leading to the straight applicability of the pattern multiplication method to the obtaining of array patterns of extremely compact antenna arrays with strongly coupled element radiation patterns. This method is found to be indispensable for compact transmitting antenna arrays designs. For compact receiving antenna arrays, a novel noise modeling method is presented for the first time to characterize the effect of noise on the performance of the array. This method is simple and effective in that it seeks to partition the array noise into two easily identifiable components, which substantially facilitates both the analysis and measurement of array noise in compact receiving antenna arrays. DOA estimation examples help to demonstrate the effectiveness of this method. Finally, the issue of beamforming in wideband compact antenna arrays is investigated in this thesis with a suggestion of an effective technique to compensate for the mutual coupling effect which inevitably affects the array?s accuracy in beamforming.