PREDICTING PERFORMANCE CHARACTERISTICS OF DOUBLE ELLIPTICAL MICRO-STRIP PATCH ANTENNA FOR RADIOLOCATION APPLICATIONS USING RESPONSE SURFACE METHODOLOGY

Double Elliptical Micro-strip Patch Antenna (DEMPA) is a newer family of patch antennas which possesses higher design flexibility and has greater potential for getting miniaturized than Elliptical Micro-strip Patch Antenna (EMPA). The DEMPA is made out of a Double Elliptical Patch (DEP) which is designed as a combination of two half-elliptical patches either with a common minor axis and two different semi-major axes or with a common major axis and two different semi-minor axes. There are only two design parameters for an EMPA, its semi-major axis and semi-minor axis, whereas a DEMPA has three because of either two different semi-major axes or two different semi-minor axes. A parametric study is required to understand the relationship among these three design parameters and antenna characteristics such as return loss, impedance, resonant frequency, and gain. The present work is a statistical study, using the concept of Design of Experiments (DOE), of the impact of these design parameters on the return loss at resonant frequency within the frequency band of 8.50 GHz-10.55 GHz which has been earmarked for radiolocation applications by regulating agency. The Central Composite Design (CCD) technique in the Response Surface Methodology (RSM) of DOE has been employed here to develop empirical relationship between the design parameters and response variable. Numerical models were developed using Ansoft's HFSS as per the design matrix provided by Minitab. The concept of DOE helped to establish statistically significant parametric relationship between the design parameters and antenna return loss with the minimum amount of design effort. The predictive ability of regression model was confirmed by using numerical models of two DEMPAs that were not utilized to build the empirical relationship, one among which had been fabricated, tested and reported in literature.