Enhancement of Scan Angle Using a Rotman Lens Feeding Network for a Conformal Array Antenna Configuration

摘要

An antenna with a wide scan angle in a wide frequency band is obtained by feeding a conformal arc array with a modified formulation of Rotman lens design. In this paper, two kinds of Rotman lenses are designed to feed a linear array and a conformal array and their scan angles are compared in a specified frequency band. The phase distributions of the linear array elements are linear in all scan angles, but these phase distributions are nonlinear in the conformal array. Therefore in order to design a Rotman lens for conformal arrays, the conventional Rotman lens design formulations must be modified. For this purpose, first the phase distributions of conformal array elements were obtained using the particle swarm optimization (PSO) process. Then by modifying the conventional Rotman Lens design formulations used for linear arrays, appropriate formulations for conformal arrays are obtained. In the end, by selecting two specified linear and conformal arrays with equal number of elements, their maximum scan angles in a specified frequency band are studied. It is shown that in the same frequency band the maximum scan angle increases about 20% in the Rotman Lens fed conformal array antenna.