Comparison of different feeding techniques of a low-profile dual-band circularly polarized microstrip antenna

This paper presents a comparison between various feeding tesingle feed aperture coupledchniques of a circularly polarized micro-strip antenna design intended to operate at the Global Navigation Satellite Systems (GNSS) frequencies. The proposed antenna is composed of a micro-strip slotted patch antenna printed on a Rogers RO3006 substrate, a foam layer of 2 mm thick. The single feed aperture coupled antenna design consisted of a single microstrip line placed on a Rogers RO3006 substrate and two ground plane slots. The dual feed aperture coupled antenna design consisted of two microstrip lines placed on a Rogers RO3006 substrate, two ground plane slots and a wideband commercial 3-dB SMT coupler. The dual feed coaxial cables consisted of two coaxial cables that are connected to 3-dB SMT coupler. The aperture coupling feed antenna design and especially the single feed design showed remarkable antenna matching and total efficiency. The combined full-wave antenna results with the measured S-Parameters of the coupler showed very good performances in terms of antenna matching and axial ratio on larger bandwidths.