Shaping And Optimization Of Reflector Antenna Based On NURBS Modeling

The reflector antenna is widely used in various fields such as radar, navigation, radio astronomy, satellite communications, atmosphere and etc. To obtain a high-gain beam or meet some special requirements, the reflector antenna needs to be shaped. In this paper, the shaped antenna is optimized by using NURBS modeling technique. The main contents and results of this paper can be summarized as followsFirst of all, the basic concepts and properties of NURBS curves and NURBS surfaces are introduced, and the deformation control of NURBS curves and NURBS surfaces is analyzed. Then, the bat algorithm is introduced to optimize the design of the bat algorithm, which has a great effect on the NUBRS surface fitting and the optimization process. The NURBS surface is used to fit the reflector antenna by changing the coordinates of the control points.Then, two kinds of analysis methods of the reflector antenna are introduced:the physical optics method (PO) and the multilevel fast multipole algorithm (MLFMA). In the process of optimizing the design of reflector antenna, in order to accelerate the calculation speed of the physical optics method, this paper introduces the graphics processor (GPU) to assist the operation, significantly improved computing speed. Reflector antenna is optimized by the bat algorithm to optimize the antenna pattern which covers a specific area.What’s more, an elliptical aperture ring-focus antenna is obtained by cutting the main reflector. The two reflective surfaces of the antenna are respectively represented by using NURBS surfaces. The main gain, the first side lobe and the azimuth of the antenna are respectively optimized by using space mapping algorithm to shape reflector antenna.Finally, to improve traditional double-offset Cassegrain antenna, the secondary reflector is changed to plane, so that the multi-beam pointing angle feed gap decreases. By optimizing the path error of the beam, the gain gap between the edge and the center beam is reduced. So multibeam seamless coverage within a range of 5 degrees.