A Novel Approach to Synthesis of Non-uniform Conformal Reflectarray Antennas

摘要

This paper presents an accurate method to synthesize a shaped-beam conformal reflectarray (RA) antenna based on the phase synthesis of its equivalent aperture. For this purpose particle swarm optimization (PSO) is used to determine the optimal phase distribution on the reflective surface of the antenna. Furthermore, a method based on meshing the aperture of the antenna has been adopted to evaluate its radiation fields. By dividing the equivalent aperture of the antenna into small parts, the induced current in each part is approximated appropriately.Then the radiation fields can be evaluated via the sum of simple integrals. This approach provides a direct correlation between the amplitude and the phase of reflection coefficient of the RA elements with the radiation fields of the antenna. Therefore, the effect of elements can be considered directly in the optimization process. Another advantage of this method is that it can be used to synthesize non-flat RA antennas. Furthermore, in the proposed method the effects of the angle, polarization, amplitude, and phase of the radiated fields from the feed antenna are fully considered in the synthesis procedure. To verify the proposed method a shaped beam parabolic RA antenna in the X-band has been synthesized. The simulation results represent a good agreement with the simulation results obtained from the commercial full-wave electromagnetic (EM) software, CST microwave studio.