A low-profile and wideband crossed dipole antenna based on AMC reflector for circularly polarized applications

Abstract

Based on the AMC (Artificial Magnetic Conductor) reflector, a low-profile and wideband crossed dipole antenna for circularly polarized (CP) applications is presented in this paper. The antenna consists of a double-sided printed crossed dipole radiator, four parasitic loops and an AMC reflector. The crossed-dipole radiator is fed by a pair of vacant-quarter printed rings, generating circularly polarized radiation. By using the parasitic loops, an additional CP mode is produced, which combines with the original CP resonance to provide wideband CP operation. Also, an AMC reflector is used here to obtain unidirectional radiation pattern and the low-profile property. To verify the feasibility of the proposed design, a prototype has been fabricated and measured. The results show good performance of 10-dB impendence bandwidth is approximately 50.0% (1.29–2.15 GHz), and 3-dB axial ratio bandwidth of 27.7% (1.4–1.85 GHz). Moreover, the prototype has a low profile of 0.11λ₀ (in terms of the center frequency of passband) and an average gain of approximately 8.9 dBic within passband.