A Compact Near-Field Resonant Parasitic Slot Helix Antenna With Wide Axial Ratio Bandwidth

Abstract

A compact near-field resonant parasitic (NFRP) slot helix antenna with wide axial ratio bandwidth is developed in this Letter. The developed antenna consists of one hemispherical metallic surface (HMC) etched with dual curved helical slots and one driven helical monopole nested beneath. The working mechanism of wideband circular polarization radiation of a single-slot NFRP helix antenna is first investigated. Then, a dual-slot NFRP helix antenna with wider working bandwidth in a lower frequency range is evolved by organically collaborating two helical slots etched on the HMC. An optimized prototype of this dual-slot NFRP helix antenna was fabricated, assembled, and tested. The measured results, in good agreement with the simulated values, demonstrate that it possesses a compact size, and an effective fractional bandwidth of 19.15% along with the realized gain values of 3.52 ± 2.25 dBic. The above advantageous performance characteristics enable it to be a good candidate in applications into many wideband space-limited platforms, such as aerospace and mobile communication systems.