Beampattern and Polarisation Synthesis of 3D Rf-Seeker Antenna Arrays

Existing missile radar seekers use a mechanical rotating antenna to steer the radiating beam in the direction of the target. Recent research is investigating the possibility to replace the mechanical RF seeker with a novel 3D conformal antenna, embedded below the radome, that can steer the beam electronically. 3D conformal antenna arrays may offer many advantages, such as a higher gain and an extended coverage, and new degrees of freedom which derive from the resulting higher flexibility in the choice of the 3D shape. Despite this, they also present new technical challenges, related to the robustness of the beampattern characteristics as a function of the steering angle, that must be addressed. The overall objective of our research is to design, prototype and assess the performance of novel 3D conformal antenna arrays for RF seekers. In order to do this, a first study has been carried out to generate and display the polarisation pattern of any 3D antenna arrays. In this paper, we present an electromagnetic antenna tool that has been developed to carry out an analysis of beamforming and polarisation for any shape of 3D antennas. The program imports the pattern of an individual element of the array and generates the global radiation pattern by coherently summing the contribution of each element. One feature of the tool is the calculation of the polarisation pattern induced by the conformation which provides a complete description of the time varying electric field of the array.