THE FRINGING FIELD AND RESONANCE FREQUENCY OF CYLINDRICAL MICROSTRIP PRINTED ANTENNA AS A FUNCTION OF CURVATURE A. Elrashidi *, K. Elleithy * and Hassan Bajwa† *Department of Computer and Electrical Engineering † Department of Electrical Engineering University of Bridgeport, 221 University Ave, Bridgeport, CT, USA aelrashi@Bridgeport.edu ABSTRACT The fringing field has an important effect on the accurate theoretical modeling and performance analysis of microstrip patch antennas. Though, fringing fields effects on the performance of antenna and its resonant frequency have been presented before, effects of curvature on fringing field have not been reported before. The effective dielectric constant is calculated using a conformal mapping technique for a conformal substrate printed on a cylindrical body. Furthermore, the effect of effective dielectric constant on the resonance frequency of the conformal microstrip antenna is also studied. Experimental results are compared to the analytical results for RT/duroid-5880 PTFE substrate material. Three different substrate materials RT/duroid-5880 PTFE, K-6098 Teflon/Glass, and Epsilam-10 ceramic-filled Teflon are used for verifying the new model. KEYWORDS Fringing field, microstrip antenna, effective dielectric constant and Resonance frequency. 1. INTRODUCTION Due to the unprinted growth in wireless applications and increasing demand of low cost solutions for RF and microwave communication systems, the microstrip flat antenna, has undergone tremendous growth recently. Though the models used in analyzing microstrip structures have been widely accepted, the effect of curvature on dielectric constant and antenna performance has not been studied in detail. Low profile, low weight, low cost and its ability of conforming to curve surfaces [1], conformal microstrip structures have also witnessed enormous growth in the last few years. Applications of microstrip structures include Unmanned Aerial Vehicle (UAV), planes, rocket, radars and communication industry [2]. Some advantages of conformal antennas over the planer microstrip structure include, easy installation (randome not needed), capability of embedded structure within composite aerodynamic surfaces, better angular coverage and controlled gain, depending upon shape [3, 4]. While Conformal Antenna provide potential solution for many applications, it has some drawbacks due to bedding [5]. Such drawbacks include phase, impedance, and resonance frequency errors due to the stretching and compression of the dielectric material along the inner and outer surfaces of conformal surface. Changes in the dielectric constant and material thickness also affect the performance of the antenna. Analysis tools for conformal arrays are not mature and fully developed [6]. Dielectric materials suffer from cracking due to bending and that will affect the performance of the conformal microstrip antenna.