Electrically Small Supergain Arrays

TL;DR

This paper presents theory, simulations, and experiments demonstrating nearly optimal supergain in electrically small two-element arrays, overcoming practical challenges through resonant antenna design, and discusses potential for larger arrays with multiple elements.

Contribution

It introduces a practical approach to achieve high supergain in electrically small arrays using resonant antennas, addressing key technical challenges.

Findings

Near optimal endfire gain of 7 dB achieved

Overcoming mismatches and efficiency issues in small arrays

Potential for larger arrays with multiple elements

Abstract

The theory, computer simulations, and experimental measurements are presented for electrically small two-element supergain arrays with near optimal endfire gains of 7 dB. We show how the difficulties of narrow tolerances, large mismatches, low radiation efficiencies, and reduced scattering of electrically small parasitic elements are overcome by using electrically small resonant antennas as the elements in both separately driven and singly driven (parasitic) two-element electrically small supergain endfire arrays. Although rapidly increasing narrow tolerances prevent the practical realization of the maximum theoretically possible endfire gain of electrically small arrays with many elements, the theory and preliminary numerical simulations indicate that near maximum supergains are also achievable in practice for electrically small arrays with three (and possibly more) resonant elements if the decreasing bandwidth with increasing number of elements can be tolerated.