Analysis And Research On Electromagnetic Characteristic Of Metal-Medium Carrier Based High Frequency Method

In recent years, with the rapid development of the application of multi-beam antenna array from multiple target-track radar, electronic countermeasure, electronic surveillance and other traditional military fields to high data rate wireless communication, automotive collision avoidance radar, base station, and other new civil fields, People begin to focus their study on both high-performance and low cost simultaneously. Compared to phased array antenna, multi-beam forming network is getting more and more attention from the antenna engineers because of low cost. Rotman lens is the most commonly used multi-beam forming network, which has many attractive features such as broadband, simultaneous multi-beam, true time delay, design simple and other prominent advantages. Since been proposed in 1963, Rotman lens is widely used in such as radar, satellite, wireless communication and other areas of the military and civil fields. At present, there are many research literature about Rotman lens, but most of them are focused on the engineering applications of Rotman lens and the research about improving the disadvantage of Rotman lens such as small scanning angle, large size, high sidelobe level and so on are a few. Therefore, it is particularly necessary to carry out studies on Rotman lens technology, including its theories, analysis methods, design, experiments and applications, so as to make the best of its potential technical advantages.Based on the basic principle of Rotman lens multi-beam array antenna, this thesis carries on research about the improvement of miniaturization, low sidelobe, wide-angle scanning and conformal array antenna. The main content of this paper is as follows:First, this thesis has made the detailed introduction to research background, domestic and international research dynamic, working principle and analysis method of Rotman lens multi-beam array antenna, and has reviewed some of typical design; this thesis successfully reduces the size of the traditional rectangular waveguide Rotman lens’ s phase transmission line by inserting pins into the rectangular waveguide or using a rectangular waveguide which has a changing broadside. Two prototypes of the improved Rotman lens multi-beam array antenna are manufactured and tested, and good accordance is obtained between simulated and measured results, which reach to the expected target.Then, a new kind of Rotman lens with single ridge waveguide is proposed to reduce the distance between two adjacent array ports, which is useful to decrease the dimension of the lens and suppress the grating lobe of array antenna when scanning in the whole working bandwidth; Aiming at reducing the sidelobe level of the array antenna fed by Roman lens, this thesis carries on research about the method of pairs of adjacent beam ports being fed at the same time and successfully improves.At last, aiming at expanding the scan angle of Rotman lens and making which to be applied to conformal array antenna, this thesis combines substrate integrated waveguide technology and R-k R lens( a special kind of Rotman lens) technology so that designs a broadband conformal multi-beam antenna array which has a wide scanning angle. Then, a prototype of the R-k R lens multi-beam array antenna is manufactured and tested, and good accordance is obtained between simulated and measured results.