Passive Shaped Beam Synthesis Using Pattern Diversity Dielectric Resonator Antenna Array

Passive antenna array is attractive for energy-efficient base station antenna. However, due to the absence of active elements, a large number of antenna elements are required to provide adequate degree of freedoms (DoFs) for shaped beam synthesis. This results in a bulky antenna structure of the conventional passive antenna array. In this work, pattern diversity dielectric resonator antenna (DRA) is firstly utilized for passive antenna array shaped beam synthesis. Pattern diversity DRA can provide extra DoFs by exciting orthogonal TE and TM modes with diverse ports. For demonstration, a four-element linear pattern diversity DRA array is designed to verify its feasibility on shaped beam synthesis. Array configurations and desired user patterns are formulated, and optimized by the artificial fish swarm algorithm (AFSA) algorithm. Its synthesis performances on six pattern shapes with different peaks and nulls are evaluated, and compared with a conventional four-element phase array. It was found that the proposed passive antenna array has better synthesis ability with smaller mean square error (MSE) than that of conventional phased array. The measured results verify the feasibility of using pattern diversity DRA as a passive scheme for energy-efficient base station antenna.