| As a kind of classic ultra-wideband antenna,the planar tapered slot antenna has the advantages of wide impedance bandwidth,high radiation efficiency,preferable symmetry of radiation patterns,low profile and so on.Vivaldi antenna and linear tapered slot antenna(LTSA)are the most famous two kinds which are widely used in radar search,earth detection,medical imaging and other fields.The Vivaldi antenna is susceptible to the thickness and dielectric constant of dielectric substrate.It is manifested in pattern splitting and gain reduction in the high frequency band.However the disadvantage of LTSA is poor impedance matching at low frequency.In this paper,the key parameters of the planar tapered slot line antenna are analyzed,and the improvement methods of its performance are discussed and analyzed in detail.The main work includes:(1)Study on the key parameters of tapered slot antenna.The influence of curvature of the tapered slot line and the dielectric constant of the substrate are simulated and analyzed,and the design criteria is explored.By comparing the performance between Vivaldi antenna and LTSA,a linear tapered slot antenna with metal parasitic patch loaded is proposed,which can improve the impedance matching characteristics of 1-3GHz band without increasing the antenna size.The simulation result verified that the all metal Vivaldi antenna has the advantages of gain and cross polarization compared with the traditional co-plane Vivaldi antenna.Double slot balanced antipodal Vivaldi antenna is designed.Compared with the conventional double slot antipodal Vivaldi antenna,the cross polarization is improved by about 10 dB in the 2-10 GHz frequency range(2)Study on the enhancement of radiation characteristics of the high frequency band of the Vivaldi antenna.Design and manufacture a metal parasitic patch loaded antipodal Vivaldi antenna,the maximum gain of the antenna in the 3-6GHz frequency range increases about 2dB compared with the conventional antenna.The method is effective especially when high dielectric constant substrate is adopted.Furthermore,the Cut-C antenna is designed and simulated by cutting the substrate between the aperture.Substrate itself shaped to a dielectric director to improves the radiation characteristics without increasing the size of the antenna.In the 8-15 GHz band,the directivity of the Cut-C antenna enhanced up to most 10 dB compared with the one using Rogers4003 substrate. |
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