International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-8 Issue-10, August 2019 4363 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number J98750881019/19©BEIESP DOI: 10.35940/ijitee.J9875.0881019 Design of Planar and Conformal Microstrip Patch Antenna for Avionics Applications Ch V Ravi Sankar, P V Y Jayasree Abstract: Microstrip patch antennas have an important role on Communication applications on satellites, aircrafts, missiles and other vehicles comparing to other types of antenna because of their conformability nature. In this paper several EM simulations performed on planar and conformal antenna for avionic applications. The design of the proposed planar antenna configuration is analyzed by using IE3D simulation software, it is MOM (Method of Moments) based and conformal antenna is analyzed by using HFSS simulator which is finite element method.In addition we are achieving circular polarization. keywords: planar microstrip patch, conformability, Method of Moment,IE3D,HFSS. I. INTRODUCTION Now a day’s mobile communication and other defence, aircraft and satellite communication systems need a compact MSA [1]. Microstrip antennas are some advantages with reference to other types such as low profile, small size and less fabrication costs. The flexibility afforded by microstrip antenna technology has led to a wide usage in avionics applications, low efficiency and narrow bandwidth and less gain are the limitations. A comparative analysis between planar and conformal antenna determines advantages and limitations of radiation characteristics. Planar microstrip antennas can be reached its maturity [2]. There can be as many as 15 different antennas or more, it gives aerodynamic drag. Placement of the antennas into the host surface is highly considerable. The conformal antenna is highly desirable on variety platforms, such as missile, rocket, UAV, satellite and aircraft. Conformal antennas are almost any geometry of the cylindrical, conical and spherical structures. The other important feature of conformal antenna is aerodynamic drag is less, integration of antenna on host surface is simple, and conformal antenna reduces the errors caused by the superstate i.e. radome.The simple conformable design is antennas on single curved surfaces; the main purpose of such design is to improve azimuth plane coverage. A vision of a future conformal antenna consists a complete RF system, including power dividers, feed network, phase shifters, etc.the main drawback of conformal antenna is negative effect on pattern of radiation because of curvature and the beam will be changed from one direction to other [3]. The directivity of conformal antenna also reduced because of surface change of antenna.To meet the requirements and to overcome the limitations of linear polarization implementation of circular polarization is more advantage compared to linear polarization. Revised Manuscript Received on August 05, 2019 Ch V Ravi Sankar*, Electronics& communication Engineering,, GITAM University, Visakhapatnam, INDIA.Email: ravisankar452@gmail.com Dr. P V Y Jayasree , Electronics& communication Engineering,, GITAM University, Visakhapatnam, INDIA. Email: pvyjayasree@gitam.edu The most important of circular polarization is less polarization loss and more resistive to signal degradation due to bad weather conditions for reflectivity, phasing issue, absorption and multipath issues [4]. II. ARRAY ANTENNA DESIGN For achieving circular polarization, two orthogonal standing waves, 90 0 out of phase are required for microstrip antenna. We have two different techniques for achieving circular polarization. One is to feed a square patch on two adjacent sides,one of the feed is delayed by 90 0 . This technique is difficult to get circular polarization. The second method for achieving circular polarization through feeding one side of the patch and truncate the square patch corners. If the square patch corners are truncated perfectly the right amount of size, there will be variance in frequencies cause the ninety degrees phase shift, a lower output impedance is achieved in this criteria [5]. The empirical equations had shown below gives the truncated size of corners and modes of circular polarized signals [6] . ∆s/S = 1/2Q ……….(eq1) f 1 = f 0 [1-(2∆s)/S] ….(eq2) f 2 = f 0 . .................(eq3) Where ∆s is perturbationarea,S denotes patch area, and quality factor of patch is Q. The patch lengthis L, then area S = L 2 and ∆s is equal to c 2 , where c is the perturbation length. The four element array consists of four corner truncated microstrippatch antennas with a feed network consists of hybrid T-junction for equal amplitude distribution RT/Duroid 5880 dielectric substrate with 1.6 mm thickness. The radius of the patch determined by a systematic approach taking into account of €r, Frequency (fr) and height of substrate (h) to be taken [14]: Practical Radius can be calculated as:          ….(eq4)     ………………(eq5) The patch effective radius as:             ……………(eq 6)