Structural Analysis of Dipoloop Antenna Radome for Airborne Applications M. Chandra Sekhar Reddy Associate Professor, Department of Mechanical Engineering, UCE (A), Osmania University Hyderabad, India Abstract - The ever increasing demands on the performance of airborne antennas place comparable demands on the design of the enclosing radome. The Airborne Radome is a structure that serves to enclose an antenna and to protect it from its physical environment. There are a wide variety of Radome types, and they can be placed on different parts of the aircraft, making its design different for each case. . The radome enclosed antenna is mounted on the bottom of the aircraft. The conception of such a unit is subjected to electrical and structural requirements, because of this, materials used for airborne radomes must have electrical and high mechanical strength properties, but unfortunately, these properties are often mutually exclusive and a compromise solution must be adopted. This paper deals about design and development of dipoloop antenna radome. The radome is exposed to the environment where in it has to sustain the mechanical loads arising from wind loads and dynamic vibration levels. The dipoloop antenna radome is made of E-Glass fibers and epoxy resin. Static wind load, Eigen value, shock analysis and random vibration analysis were carried out using FEA (Finite Element Analysis) to investigate whether the radome withstands the wind loads and the dynamic vibration. Keywords – Radome; static analysis; dynamic analysis; dipoloop antenna. I. INTRODUCTION Radomes are used to enclose antennas. The main function of a radome is to provide protection for the enclosed equipment (antenna and other electronics). This improves system availability since the antenna is not affected by winds, rain or ice. It also provides a stable environment for service personnel from harsh weather conditions. The benefits are reduced structural requirements, reduced fabrication, and reduced installation, maintenance costs. The radome design has to meet electrical and structural requirements of the radar. The electrical requirements are high transmission, low reflection, far-field radiation pattern, power transmittance, low absorption and small bore sight errors among others and the structural requirements are high structural rigidity against wind loads and dynamic vibration levels. The requirements may be met by the selection of the appropriate materials and by maintaining the correct wall thickness. Junaid Hussain Research Scholar, UCE (A), Osmania University Hyderabad, India The Dipoloop antenna consists of a combination of dipole antenna and loop antenna which are connected parallel with respect to feed point and are oriented in orthogonal planes. Omni directionality for vertically polarized waves is supported by vertically positioned dipole element while omni directionality for horizontally polarized waves is supported by horizontally positioned loop. Materials used for airborne radomes must have low dielectric constant and high mechanical strength, but unfortunately, these characteristics are often mutually exclusive and a compromise solution must be adopted. Composites are gaining wider acceptance for use on airborne, ship-borne, and submarine applications due to number of advantages viz. high strength to weight ratio, ability to be molded into complex shapes, absence of corrosion palliatives which otherwise are source for electronic and magnetic signature. Composite materials made from E-Glass fibers and epoxy resins have become very popular as a radome material due to its outstanding transparency to microwaves and good mechanical properties. Uses vary from large terrestrial installations, air traffic control, and aviation installations. Typical applications include antennas for radar, tracking, communications, surveillance, and radio astronomy. A. Literature Review Brief report of the literature carried out for this project is given below: A. Ramesh Kumar, S.R. Balakrishnan, S. Balaji [1] has presented paper “Design of an Aircraft Wing Structure for Static Analysis and Fatigue Life Prediction”. In this paper detailed design of trainer aircraft wing structure made by using CATIA V5 R20. Then stress analysis of the wing structure is carried out to compute the stresses at wing structure. The stresses are estimated by using the finite element approach with the help of ANSYS-12 to find out the safety factor of the structure. In a structure like airframe, a fatigue crack may appear at the location of high tensile stress. Life prediction requires a model for fatigue damage accumulation, constant amplitude S -N (stress life) data for various stress ratios and local stress history at the stress International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 www.ijert.org IJERTV4IS030624 (This work is licensed under a Creative Commons Attribution 4.0 International License.) Vol. 4 Issue 03, March-2015 724