The Simulation Research Of An S-Band Low-Sidelode Antenna

The sidelobe level is an important factor in designing of antenna arrays. At present, the importance of sidelobe exceeds that of the gain and the main lobe width on a lot of occasions. There are a great number of interferences in radar communication, and the sidelobe interference is the main form of these. In fact, no only radar communication, the low sidelobe antenna is of great importance in anti-jamming technique both positive and negative with strong clutter back-ground, passive location and anti radiation missile as well. So a lot of researches focus on the low sidelobe antenna home and abroad.An S-band low sidelobe antenna is designed and proposed which fosters the character of small size and simple structure with wide bandwidth in this paper. The antenna to be discussed takes the advantage of short-focus paraboloidal reflector with round chip and is fed with half-wave dipole. Simulation results illustrate that the antenna satisfies the low sidelobe character through a wide frequency range. Besides, within the frequency range of the central frequency the antenna shows ultra-low sidelobe. At the same time, the collision between low sidelobe and beam width is solved successfully.At first, the meaning and standards of low sidelobe antenna are briefly introduced. The principles of the low sidelobe are analysed. The problems to be solved in the course of the realization method of the low sidelobe of array antennas and reflector antennas are pointed out, and the Cassegrain antenna is taken as an example to illustrate the affecting factors and the improvement on the method for the low sidelobe.Secondly, the aperture field distribution characteristics when the main reflector is a parabolic is analysed by current element methord. A simulation model of reflector low sidelobe antenna is set up.At last, the effects on the low sidelobe of the ratio of focal distancer and diameter and size change of assistant reflector have been discussed. The significance order of the factors affecting the low sidelobe is pointed out. Base on the theoretical analysis and simulation results, a low sidelobe antenna is designed which has small size and simple structure. The antenna contributes to the portable device for its short vertical length. Approximate calculation of radiation attribution of half-wave dipole feed with round chip is also discussed by simulation analysis, and the utilization coefficient of aperture field is derived.