A Method for Tailoring the Gain Pattern of a Single Antenna Element

Abstract

In this paper, we present a novel method to tailor the radiation pattern of an antenna element, such as a single element of an array, by maximing its partial radiation efficiency in the desired angular space. The tailored pattern of the single element is achieved by current distribution synthesis using multiple feed points in the antenna. A method to determine and realize the currents at the feeds is presented. The method is demonstrated by designing and manufacturing a four-element linear array consisting of tailored antenna elements and comparing its performance to the reference case. The element consists of four closely-spaced metallic patches placed on a substrate backed with a ground plane, and each patch is separately fed. The initial four-port feed is reduced to a single feed with a feeding network based on the determined currents. A conventional patch antenna is chosen as the reference. The simulated and measured results show improvement in the realized gain in the desired angular space.

A Method to Co-Design Antenna Element and Array Patterns

“…The proposed method is a major extension to the earlier works, where a multi-port antenna has been optimized in terms of port currents while maximizing the radiation efficiency [17], or the partial radiation efficiency in a certain angular range [18]. The earlier work [18] has covered optimization of single multi-port antennas and an array separately, whereas in this paper, we aim to optimize both antenna array and its multi-port antenna elements simultaneously. We create a model for determining the realized gain at different angles as a function of element-level port impedances and signals, and array-level weights.…”

“…where H denotes the Hermitian transpose, and a is a column vector of length M containing the port signals a m . Following [18], vector a is defined as…”

“…where K l (θ k , φ k ) gives the relation between the far field at angle θ k and φ k and the current i l at port l. For more information on vector K l (θ k , φ k ), see [20]. Note that variants of the radiation matrix are also shown in [17], [18].…”

Synthesis of Reactively Loaded Sparse Antenna Arrays Using Optimization on Riemannian Manifold

“…Recent research has shown that the FoV can be successfully limited by constructing the array elements from fixed sub-arrays [3]- [7]. The sub-array approach can be further improved by synthesizing matching circuits for the individual sub-array elements [8]. However, the viability of sub-array techniques depends on the availability of sufficient space for sub-array feeding networks.…”