Wide Beam Reflective Spiral Antenna

In this paper, the traditional reflective plane spiral antenna made some improvement design, through the use of dielectric lens and nonmetal cavity design of broadening the antenna beam, improved the rotational symmetry of pattern at the same time; Spiral surface coating absorbing material such a structure to optimize antenna axis ratio; Go on with the antenna on the whole optimization, finally obtained the bandwidth is 3:1 reflex mechanism forms of planar antenna, the form compared with the existing back cavity structure of the antenna is very superior performance.In this paper:Use the antenna radiation mouth increases medium spherical cap radome and the traditional metal cavity is replaced with nonmetal cavity is to transform the abnormity reflection cavity approach to effective broadening antenna beam, make it from the conventional- 30 ° to 30 ° ~ +- 50 ° ~ 50 °, the medium of spherical lens is originally divergence of electromagnetic waves using the physical properties of the lens to make it into a parallel rays, so that the mouth of the antenna surface field no longer ups and downs, but evenly to function, and the dielectric lens can help focus, the last of the energy in the process of transmission to also won’t spread too much but tend to be concentrated, electrical performance of antenna gain is significantly increased.Old normal reflection cavity wall is composed of the metal materials will produce very big effect to the antenna out images, metal wall will antenna beam coverage is compressed, at the same time, due to the metal wall multiple reflection makes the distortion of the working frequency band and high-end pattern, causing each section on the direction of the range chart, by reducing the height of the metal wall, so that on the one hand can eliminate the influence of wall for high-end direction figure, on the other hand can also be appropriate to expand the beam width of antenna and the metal base plate to backward propagation of electromagnetic waves bounce back and get a better effect.Put forward by using absorbing material above the helicoid echo method, improved antenna axis ratio, the axial ratio in the range of frequencies are less than 3, improved the rotational symmetry of pattern at the same time, make its H plane basic consistent with the pattern of E; Finally optimize the whole antenna, designed the reflective plane spiral antenna bandwidth is 3:1, the radiation characteristics comparing with the traditional back cavity helical antenna has great improvement.Article will surface in the form of production process and new antenna measurements were recorded in detail, at the same time we have to do certain preliminary simulation, and also the result of the experiment and compare the data obtained from the simulation time. By comparing the results can be clearly seen the new wide beam reflective spiral antenna conventional helical antenna performance is more outstanding than ever before.