A New Method for Gain Prediction of Superdirective End-Fire Arrays

Abstract

The problem of gain estimation of a superdirective dipole-based end-fire array is discussed in this contribution. The current method to compute the gain, for a given element radiation efficiency, is based on the array factor (AF) theory. This work is intended to show that an equivalent formulation can be done using the Spherical Wave Expansion (SWE). Besides the interest in validating the theory, the main objective is a better understanding of the radiation and attenuation phenomena that occur in compact and superdirective arrays. The limits in their practical implementations are imposed by the high sensitivity of the system. The SWE theory provides more information in the expression of the radiated field, thus unfolding the possibility to address the problem with lower sensitive solutions.

Optimization of Super-Directive Linear Arrays with Differential Evolution for High Realized Gain

“…It is crucial to emphasize that in a ULA, the maximum radiation is directed symmetrically to the x-plane in the broadside direction (φ = 90 • ). However, it is widely recognized that super-directive arrays achieve peak radiation in the end-fire direction [11], [14]. When we introduce the necessary phase adjustments to orient the ULA towards the end fire, the resulting gain is 5.82 dB.…”

“…Although there are limited studies on the realized gain (e.g. [14]- [16]), to the best of our knowledge, there has yet to be any previous work optimizing the realized gain by an iterative algorithm verified by a full wave electromagnetic simulation program. Against this background, our paper makes the following main contributions:…”