Study And Implementation Of An X-Band Antenna For Marine Navigation Radar

Marine navigation radar is the essential equipment for ships to observe coastlines, bridges, buoys and so on. As one of the main parts of a radar system, antenna system directly affects the performance of the whole radar. At present, a traditional antenna is always used in many medium marine navigation radars. The antenna is fed in the single-ended of waveguide and it is a travelling wave antenna. The feeding structure of the antenna is relatively complicated. And it brings about more transmission loss. At the same time, the balance of the antenna is destroyed by the asymmetry of the structure. So the antenna would decrease the ability to resist wind.In this thesis, a new type of marine antenna is designed from multiple perspectives, such as the performance indicators, the design cycle, the machining difficulty and so on. This design adopts the coaxial feed in the middle of the antenna to reduces the difficulty of the design of the servo system and reduce the feeding transmission loss. And the standing wave antenna, instead of the traditional travelling wave antenna, can avoid the electromagnetic energy loss which terminal load brings about. And in the design of antenna array, this thesis uses an approximate design method by adding metal plates to divide array. This method can cut down the design cycle of the antenna array. At the same time, the experiment proves the feasibility of this method. The experimental results show that the gain of the antenna is28.3dB, the first sidelobe level is lower than-20.5dB, the horizontal beam width is2.1°.In addition, the zero-refractive-index materials is analyzed briefly in this thesis to try to use the materials in marine antenna. The simulation results show that under the condition of keeping the size of the surface caliber of the antenna, the materials can improve the gain of the marine navigation radar antenna.