Loading Spiral Antenna Ebg Structure Research

With the rapid development of ultra-broadband imaging, ultra-wideband radar, ultra-wideband electromagnetic pulse weapons, the need for ultra-wideband antenna technology for further study and put forward the requirements of ultra-wideband antenna miniaturization and conformal. The equiangular spiral antenna which is an ultra-wideband antenna is required small or conformal in a particular installation space. But in the case of the equiangular spiral antenna miniaturization and conformal the axial ratio is increased and gain is reduced. So the radiation and accept of Equiangular spiral antenna is severely affected, there is an urgent need for a miniaturization of the shape of the antenna structure, the total shape of the case, reducing the axial ratio and increase the gain does not change, but There is no related news In the domestic.Based on the above issues equiangular spiral antenna and the EBG structure design theory and method were studied. This paper presents a method which is the small EBG structures embedded in the equiangular spiral antenna does not destroy the original antenna miniaturization and conformal to reduce axial ratio and increase the gain.The main work includes the following aspects:1. Understand the principle of ultra-wideband spiral antenna radiation and the theory of electricity band-gap structure2. Analysis of EBG unit gap width, the thickness of the size, size, the size of the metal through hole on the performance of the spiral antenna. A novel low-profile equiangular spiral antenna(EAS-EBG antenna) is studied which insert a small area of electromagnetic band-gap (EBG) structure into EAS-PEC antenna to maintain a low profile and do not expand the cross-section area optimized axial ratio. The result of simulation shows that the EAS-EBG antenna reduces the axial ratio and do not reduce the gain. This also presents a viable way to improve the axial ratio of such low-profile equiangular spiral antenna with does not change the dimensions3. Using the second step of the theory, conformal equiangular spiral antenna on the circular truncated cone with electromagnetic band-gap structure is studied which inserts a Small area of electromagnetic band-gap structure into the circular truncated cone to maintain the conformal and Increase gain. The result of simulation shows that the gain of the conformal equiangular spiral antenna on the circular truncated cone inserted EBG is increased and axial ratio remains unchanged. This also presents a viable way to improve gain of such conformal antenna.4. Design the microstrip balun for matching the balanced radiator and the impendence of the antenna by using HFSS software;5. Make the whole model of the equiangular spiral antenna in HFSS software and modify the parameters of the balun and EBG by the simulation results;6. Based on the researches above, make the operation drawing of the radiator and microstrip balun by AutoCAD software, then carry out experimental study of the antenna. Test results and simulation results agree well.