Higher order tangential vector finite elements for 3-D antenna array structures

The radiation properties of several contemporary array structures in three-dimensional problems are numerically investigated by implementing an advanced second-order tangential vector finite element (TVFE) methodology. The choice and the development of the proposed strategy is justified, since it provides a more precise field representation compared to the first-order edge elements and enables its utilization within coarse meshes without reducing the accuracy of the calculated solution. The latter observation becomes more important when electrically large domains are modeled, as their study with low-order elements usually calls for a fine discretization and, consequently, results in a large number of unknowns. In this paper we mainly focus on arrays of patch antennas with linear and planar configurations, while cases where beam steering is investigated are also taken into account. For comparison purposes, our study incorporates results obtained with a higher order nonstandard finite-difference time-domain (FDTD) method, which efficiently overcomes some of the deficiencies concerning the conventional Yee algorithm.