The Design And Simulation Of Missile Borne Ultra Wide Band Antenna

The concealment and anti-jamming features of precision-guided missile has a higher bandwidth requirements on missile-borne antenna. Moreover, missile-borne antenna must have a low profile height to ensure the aerodynamic shape and flight performance in the restricted installation space of missile-borne applications. Therefore, the superior performance of the ultra-wideband antenna and conformal antenna become an important research direction. Archimedean spiral antenna and improved form of square spiral antenna are designed at caliber as planar passive ultra wideband antenna under the carrier of active and passive seeker. In order to reduce caliber area, Vivaldi antenna and antipodal Vivaldi antenna are designed as conformal passive ultra wideband antenna under the cylindrical surface of missile. The main contents of this paper are summarized as follows.First, CPW fed Vivaldi antenna is designed. On this basis, ellipse slot is used to change the antenna surface current distribution and finally realized the purpose of improving the end-fire characteristics. In order to make ellipse slot load Vivaldi antenna achieve miniaturization, side-fed makes the size of the antenna reduced by 20%. Finally, conformal Vivaldi antenna is designed under the cylindrical missile surface. By changing the conformal carrier radius, we discussed the variation in conformal antenna performance under different curvatures.Secondly, antipodal Vivaldi antenna is designed. Then, rectangular slot is used to change the surface current distribution of the antenna and finally improved the end-fire feature. Since the active and passive seeker has a higher requirements on antenna gain. Ellipse parasitic patch is introduced to increase the gain at the end of radiation zone of the antipodal Vivaldi antenna because of the enhanced coupling between the arms. Simulation results show that the average gain of the antenna is increased by 2.5d Bi. In order to achieve normal radiation and end-fire feature, Vivaldi antenna which is conformal to the cylindrical missile surface requires a certain distance from missile or radome. The method of loading dielectric substrate is introduced to achieve the purpose of miniaturization and sustain. The introduction of dielectric substrate makes low-frequency of Vivaldi antenna widened 430 MHz. Finally, we discussed performance changes of antipodal Vivaldi unit under the cylindrical conformal and conical conformal carrier. Then the performance of conformal antenna array and the effect of missile body are also considered.Finally, we designed Archimedean spiral antenna at caliber. In order to obtain unidirectional radiation, cavity is added in the back of the antenna. The introduction of cavity makes VSWR at low frequency jitter. Resistances are loaded in antenna terminal arm since it can absorb terminal reflection current thus low-frequency VSWR is improved. For the valuable caliber space, we proposed improved form of square spiral antenna to make better use of caliber space compared to Archimedean spiral antenna in this paper. Actually, antenna and radome are used together. Therefore, we explored the influence of radome on Archimedean spiral antenna and improved form of square spiral antenna radiation performance.