Comparison Analysis of Rectangular and Circular Patch Microstrip Antennas with Dielectric Superstrates

In this paper compared the characteristics of coaxial probe fed rectangular and circular patch microstrip antenna with and without Superstrates. The antenna designed at frequency of 2.4GHz(ISM band) and formulated using transmission line and cavity model analysis. In this paper experimentallyinvestigated the effect of dielectric Superstrates onthe parameters such as bandwidth, beam-width, gain, resonant frequency, input impedance, return-loss and VSWR etc. Experimental measured results shows that when placing the Superstrateabove the substrate the antenna parameter will be changed and antenna resonant frequency will be shifted lower side, while other parameters have slight variation in their values. In particular, the resonant frequency increases with the dielectric constant of the Superstrates thickness. In addition, it has also been observed that return loss and VSWR increases, however bandwidth and gain decreases with the dielectric constant of the Superstrates thickness. Impedance characteristics are that both input impedance and the reactancewhich are increased as Superstrate become thick and its ∈ increases.