Isolation improvement between loop antennas with absorber cells

This paper presents a new method to improve isolation between two loop antennas with absorber cells exhibiting negative permittivity and permeability at the aimed frequency of 2.45 GHz. The metamaterial (MTM) unit cell was constructed by two open complimentary split ring resonator (OCSRR) and a split ring resonator (SRR) arrangement. The proposed antenna structures were composed of two loop antennas occupying a space with the dimensions of 51 mm × 24 mm × 2 mm and three absorber cells. The size of each absorber unit cell was 7.4 mm × 7 mm × 2mm. The isolation of more than -20 dB was achieved with three absorber cells loaded between two loop antennas; inter-antenna spacing (center to center) was 0.23 λ₀ at 2.45 GHz. The results show that port isolation can be improved with absorber cells between two antennas.