A Novel Electrically Small Antenna Array Employing Opposite-Handed Chiral Parasitic Elements

TL;DR

This paper introduces a compact electrically small antenna array design using opposite-handed chiral parasitic elements to reduce mutual coupling and improve performance.

Contribution

It presents a novel antenna array configuration with chiral parasitic elements of opposite handedness, experimentally validated for enhanced performance in dense arrays.

Findings

Achieved a -10 dB return loss and 5-15% fractional bandwidth.

Demonstrated full 360-degree azimuthal beam steering.

Realized gain of 5 to 9 dBi in a compact array.

Abstract

This paper presents a novel concept for electrically small antenna arrays incorporating chiral parasitic elements of opposite handedness. This configuration mitigates the detrimental effects of electromagnetic mutual coupling, which in conventional arrays causes a 180 degree phase shift between adjacent antenna currents when the element spacing is less than half a wavelength. The proposed approach is experimentally validated using a seven-element monopole ESAA with compact dimensions, specifically below half-wavelength in cross-section and one-sixth to one-fourth of a wavelength in vertical range. The antenna elements are spaced less than one-sixth wavelength apart, ensuring a highly compact footprint. Measurements show a minus 10 dB return loss, a fractional bandwidth of 5 to 15 per cent, and a realised gain of 5 to 9 dBi, along with full 360 degrees of azimuthal beam steering. The results confirm that employing oppositely handed chiral parasitic elements can significantly enhance performance in densely packed, electrically small antenna arrays.