International Journal of Electrical, Electronics and Data Communication, ISSN: 2320-2084 Volume-3, Issue-10, Oct.-2015 Study Of A Novel C-Band Circular Slot Antenna Having Frquency Band-Notched Function 5 STUDY OF A NOVEL C-BAND CIRCULAR SLOT ANTENNA HAVING FRQUENCY BAND-NOTCHED FUNCTION S.RAJAN Information and Telecommunication,SRM university,Kattankulathur-603203 E-mail: sahilrjn72@gmail.com Abstract- The Circular slot antenna is designed for C-Band(4Ghz-8Ghz) is suitable for mobile applications centre frequency at 5 GHz. It contains 12 semicircular iteration section, each section is 1mm wide produce fringing effect. The proposed antenna has a compact size, good radiation characteristics, wide band-width of 4.6 GHz to satisfy the requirement of the current wireless communication systems. Antenna parameters like return loss(S11), gain, VSWR and radiation pattern are calculated and simulated and compared. The design and simulation is done using HFSS v13 simulation tool and it is fabricated on a FR4 Epoxy and RT duroid 5880 dielectric substrate. Keywords- FR4 Epoxy; RT Duroid 5880; Circular Slot Microstrip Antenna; Gain; Directivity; HFSS I. INTRODUCTION Modern Wireless communication Systems require low profile, lightweight, high gain and simple structure antennas to assure reliability, mobility, and high efficiency .A patch antenna is very simple in construction using a conventional microstrip fabrication technique. It consists of a patch of metallization on a grounded dielectric substrate. They are low profile, lightweight antennas, most suitable for aerospace and mobile applications. Patch antennas have matured considerably during last years, and many of their limitations have been overcome. In our study we are interested in circular slot by introducing stubs in circular patch because of their small size compared with other shapes which is desired in wireless communication. In this study, several designs of circular slot antennas are presented in Fr4 Epoxy and RT Duroid. We will compare simulation result of both dielectrics. Moreover, these designs are simulated using HFSS. Based on the simulation results, comparison between both dielectrics is achieved in C-Band. This band contains frequency ranges that are used for many satellite communications transmissions, some Wi-Fi devices, some cordless telephones, and some weather radar systems. This paper is divided into five sections: the first section is devoted to give an overview of the patch antennas in and a preface of the important parameters in single element designs, for both and circular Fr4 Epoxy and RT Duroid 5880 substrates. Second section discusses the Design,Procedure and presents simulation results for Paper Submission. Third section presents a comparison between both substrates simulation results. Finally, a brief conclusion is presented in the fourth. II. ELEMENT STUDY 2.1. Theory Circular slot antenna design in C-band and with optimal characteristic is the overall objective of this section. To achieve this overall objective, the primary task is to choose a suitable geometry of the patch for the antenna. The proposed shape is circular slot frequency band notch function patch for review. The study of return loss and gain show that the antenna has a band-notched characteristic at 5-GHz C band. An important and notable feature of this antenna set up is the 50 ohm microstrip line with elliptical shaped stubs on the opposite side of the substrate. The microstrip feed line width is 4.9 mm in RT duroid and 3.0mm width in FR4 Epoxy with 12 C shaped Stubs iterations of 1mm wide. Figure 1. Shows Structure of Circular slot antenna with 12 semicircular iteration 1mm wide and Partial Ground plane of RT Duroid and FR4 Epoxy with feed line width 4.9mm and 3mm respectively. For circular slot antenna, suppose patch length is L, patch width is W, dielectric thickness is h, dielectric constant is εr, light speed is c, resonant frequency is fr, wavelength is radius of circular patch a, we found in equation (1) . a๐ = aට1+ ଶ୦ ஠ୟக୰ [ ln ( πୟ ଶ୦ ) + 1.7726 (1) Δƒ is bandwidth, ƒ๐ is center frequency and VSWR is Standing wave ratio in equation (2). Δƒ ƒ๐ = ୚ୗ୛ ଵ ୕√୚ୗ୛ (2) z๐= ଵଶ଴஠ [ ౓ ౄ ାଵ. ଷଽଷ ା మ య ୪୬ ౓ ౄ ାଵ. ସସସ] √க୰ (3) Z๐ is Normalized Impedance is obtained by putting the value of patch width is W, dielectric thickness is h, dielectric constant is εr in last equation.