Investigations On Dual-polarized Vivaldi Antenna

The antenna is the most front-end of the system of modern radar,communication and so on,which purpose is transmitting and receiving the different frequencies of electromagnetic waves.The performance of the antenna influences the performance of the whole system directly.We know that the early ultra-wideband(UWB)signal is the "by-product" that was inevitably produced in completely radiofrequency events did not attract enough attention.But with the development of radio technology,radio system evolution toward a higher frequency and bandwidth increase,UWB system and re-enter the researchers' vision and gradually become a hot research topic.As an important component of UWB system,the performance of UWB antenna has great limit on the system performance.So how to improve the performance of UWB antennas and design miniaturization,high gain,double polarization and even multi-polarization ultra wideband antennas is one of the key technologies of UWB system.In this paper,the author focuses on the design of Vivaldi antennas with miniaturization,high gain and dual-polarization.In the first place,in this paper,we briefly introduce some common ultra-broadband systems and the requirements of UWB system for antenna performance.At the same time,we summarize the some kinds of common ultra-band antennas and compare its performance.The development history,research status and the development trend of Vivaldi antenna are also introduced in detail which have laid a foundation for the research in this paper.In the second place,in this paper,the author introduces the several hot spots of research of Vivaldi antennas at present,and summarizes several ways to improve the performance of Vivaldi antennas.Based on the study of the basic structure and radiation mechanism of the antipodal Vivaldi antenna,the author used the design method of the antipodal Vivaldi antenna and designed an antipodal Vivaldi antenna with a Rectangular slot edge(RSE).The antipodal Vivaldi antenna was fabricated and measured.With the help of RSE,The measured results show that the RSE can extend the low cutoff frequency and improve the radiation performance of Vivaldi antenna at lower frequencies.At the same time,when Vivaldi antenna working in higher frequency,with the increase of frequency,the phase error in the antenna aperture becomes more serious,which leads to the split of the radiation pattern,and the gain is decreased.On the basis of present research,this paper puts forward a multi-layer planar dielectric lens loading method.According to its working principle,the author designed an antipodal Vivaldi antenna with multi-layer planar dielectric lens,which has the wider bandwidth and higher gain.The antipodal Vivaldi antenna has fabricated and measured,and the measured results verify the effectiveness of the multi-layered dielectric lens loading method.In the third place,this paper introduces the research status of dual-polarized Vivaldi antenna.At the same time,based on the equivalent circuit of the conventional Vivaldi antenna,the radiation mechanism of the conventional Vivaldi antenna is studied and the general design guidelines are given.And then,a conventional Vivaldi antenna with RSE was designed which has small antenna size and works in x-band.The dual-polarized Vivaldi antenna with two Vivaldi antennas which have different feeding point positions in a cross-shaped form,and the two Vivaldi antennas with a galvanic contact in soldering point.The dual-polarized Vivaldi antenna has fabricated and measured,and the measured results verify the effectiveness of the design method.Finally,in this paper,the author designs a traditional dual-polarized Vivaldi antenna array and a antipodal dual-polarized Vivaldi antenna array.At the same time,the array performance between traditional dual-polarized Vivaldi antenna array and a antipodal dual-polarized Vivaldi antenna array is compared and summarized.In the end,the antipodal dual-polarized Vivaldi antenna array has been fabricated and measured and the measured results show that the antenna array has good radiation characteristics and polarization purity and can be applied to a variety of UWB systems.