Design of dielectric-loaded compact broadband circularly-polarized helix antenna by using multiobjective evolutionary algorithm based on decomposition (MOEA/D)

This paper presents the design of a compact broadband circularly-polarized helix antenna. The proposed antenna consists of a low-profile metal-strip helix structure fed by a coaxial probe and three different dielectric blocks. In this design, dielectric materials with high permittivity are for miniaturization. All dimensions of the design are obtained by using multiobjective evolutionary algorithm based on decomposition combined with differential evolution (MOEA/DDE). Simulation results show the 10dB impedance bandwidth, 3dB axial-ratio bandwidth, and gain of more than 6dBi over the band of 1.88GHz-2.69GHz. The overall size of this design is 28mm×28mm×32mm (0.21λ×0.21λ×0.24λ at 2.3GHz). The proposed antenna is attractive for indoor distributed antenna systems supporting Long Term Evolution (LTE) middle band.