Research Article A Novel Performance Analysis of the Microstrip Antenna Printed on a Cylindrical Body Amr M. Mahros, 1,2 Marwa M. Tharwat, 3 and Ali Elrashidi 4 1 Department of Physics, King Abdulaziz University, Jeddah 21432, Saudi Arabia 2 Department of Engineering Physics, Alexandria University, Alexandria 21544, Egypt 3 Department of Electrical & Computer Engineering, King Abdulaziz University, Jeddah 21432, Saudi Arabia 4 Department of Electrical Engineering, University of Business and Technology, Jeddah 21432, Saudi Arabia Correspondence should be addressed to Amr M. Mahros; amr.mahros@mena.vt.edu Received 30 September 2014; Revised 22 November 2014; Accepted 23 November 2014; Published 11 December 2014 Academic Editor: Jaume Anguera Copyright © 2014 Amr M. Mahros et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Performance of a circular patch microstrip antenna is highly afected by the efective dielectric constant of a used substrate material. When the circular patch is conformed on a cylindrical body, the efective dielectric constant is changing with curvature due to the changing in the fringing feld. Consequently, some of antenna parameters such as resonance frequency, input impedance, voltage standing wave ratio, return loss, quality factor, and antenna bandwidth are functions of curvature. In this work, we study the efect of curvature on the performance of circular patch microstrip antenna. A mathematical model for the antenna parameters as functions of curvature is also introduced. Te model is applied in case of using two substrates of diferent refractive index values. By extension, the antenna performance was studied through simulation by using method of moments (MoM) which is reliable in solving Maxwell’s integral equations in the frequency domain. Te results from simulation compare very favorably with the described analytical results. 1. Introduction Circular patch microstrip antenna is widely used in recent wireless applications such as aircraf communications, Blue- tooth, HIPERLAN, and medical imaging [1–4]. A microstrip antenna has received extensive research due to its low cost and small size. Tis antenna can be easily fabricated and conformed on cylindrical bodies [5–7]. Conformal antennas, in general, have some advantages over planner microstrip antennas such as wide angular coverage and controlled gain [8, 9]. Te main drawback of microstrip antennas is their narrow bandwidth which results in high sensitivity to any frequency change and decreases the efciency of their overall performance [10]. In this paper, we introduce the efect of curvature of a con- formed circular microstrip printed antenna on the efective dielectric constant, resonance frequency, input impedance, voltage standing wave ratio (VSWR), return loss ( 11 ), qual- ity factor, and bandwidth of such antenna. Furthermore, the mathematical equations for these parameters as functions of curvature for cylindrical surface are also reported in this paper. Te analysis is considered at resonance frequency of 2.4 GHz and transverse magnetic mode TM 01 for two diferent substrate materials with dielectric constants of 2.1 and 10. Tough it was mentioned that changing the radius of curvature of a cylindrical body has no efect on the resonance frequency of a circular patch microstrip antenna printed on a cylindrical body, the experimental results show a bit shif on the operating frequency for diferent curvature [11]. Te debate emerged as there is no clear explanation for this shif that had been introduced. We have introduced comprehensive mathematical equa- tions that show the efect of curvature of a cylindrical body on a rectangular microstrip printed antenna [12]. Te theoretical results were compared to experimental results to verify the introduced model. In this work, we extend the model to study the curvature efect on a circular patch microstrip antenna printed on Hindawi Publishing Corporation International Journal of Antennas and Propagation Volume 2014, Article ID 613245, 9 pages http://dx.doi.org/10.1155/2014/613245