Computer-Aided Analysis for Tangent Ogive Airborne Radome Using Physical Optics Method

Abstract

Airborne radar antennas are usually enclosed in dielectric radomes for protection from a variety of environmental and aerodynamic effects. However, the presence of the radome will affect the radiation performance of the enclosed antenna significantly, due to interactions between the antenna and radome. The ever-increasing demands on the performance of airborne antennas place comparable demands on the design of the enclosing radome to ensure minimal degradation of the antenna radiation pattern. The geometry of the radome being largely determined by aerodynamic consideration, often leads to severe degradation of the electrical performance of the enclosed antenna. For airborne radomes, to withstand the aerodynamic drag, the shape is chosen to be tangent Ogive. The Physical optics method using the appropriate ray paths are implemented to analyze the performance of the monopulse slotted array antenna enclosed by the tangent Ogive shaped radome. The developed software will take antenna slot co-ordinates and the excitations, and radome geometry & material properties as input. The output of the software is the antenna radiation pattern with and without the radome. It also gives the boresight error with respect to scan angle It compares the two to give the distribution in beam width, side lobe level etc., due to the enclosing radome.

Aerodynamic Optimization of Airborne Radome for Maritime Patrol Radar

“…A. et al [6] have discussed the design aspects of dielectric airborne radomes. It is highlighted that the design of radome is generally driven by aerodynamic considerations.…”

“…4 shows the radome 3D shape and minimum swept volume required for installation of antenna inside the radome. (6) where J(x) is Drag due to radome and x is vector of design variables (as given in Table 1). Aim of the optimization study is to arrive at a radome shape for which the drag experienced is minimum, at the selected operational point of the maritime aircraft.…”

Efficient design of a radome for minimised transmission loss

“…The nominal matched thickness (RMT) for a radome can be calculated from Equations (1) and (2) where λ m is the wavelength in the material, λ o is the wavelength in free space of the Electromagnetic Radiation (EMR), r is the relative permittivity, n is an integer and α i , is the angle of incidence of the EMR. Before the common use of EM simulations to calculate the radome thickness a radome would be manufactured over-thick by several mm, RF tested, the thickness reduced, RF tested and iterated until the optimal thickness was found.…”

Development of Silicon Nitride‐Based Ceramic Radomes — A Review

“…For airborne radomes, the shape is chosen to be tangent ogive to withstand the aerodynamic drag . The ogival shape has several advantages such as slightly greater volume for a given base and length, a blunter nose, providing structural superiority and slightly lower drag .…”

“…20 For airborne radomes, the shape is chosen to be tangent ogive to withstand the aerodynamic drag. 21 The ogival shape has several advantages such as slightly greater volume for a given base and length, a blunter nose, providing structural superiority and slightly lower drag. 22 The profile of tangent ogive is formed by a segment of a circle such that the rocket body is tangent to the curve of the nosecone at its base; and the base is on the radius of the circle as shown in Fig.…”