Dual-band microstrip patch antenna using capacitive artificial magnetic conductor

In this paper, the capacitive value used in a structure of artificial magnetic conductor (AMC) is investigated for achieving dual-band frequency responses of microstrip patch antenna. The implemented structure is a planar structure which consists of four identical square patches arranged in 2x2 array incorporated with capacitors placed between adjacent patches. The proposed antenna takes a total dimension of 52mm x 52mm. The AMC structure and antenna are deployed on FR4 Epoxy dielectric substrate with relative permittivity of 4.4 and total thickness of 3.2mm. From the characterization result, it is shown that the incorporation of surface-mount capacitor on AMC structure could produce dual-band frequency responses at 1.42GHz and 1.59GHz. However, the gain of antenna with capacitive AMC at the resonant frequency is lower than of the antenna without capacitive AMC. Meanwhile, the bandwidth is also narrower as the use of capacitive AMC.