According to the parameters of a Brown Big-eared bat's pinna,a simple obliquely truncated bat ear model that made by line and plane was designed,which was numerically simulated with finite element method.The change of far-field directivity was analyzed in elevation and azimuth as the frequency increased.The results show that,compared with the pinna of the Brown big-eared bat,the present model has the advantages in wider bandwidth of frequency driven scanning,better directivity in azimuth and larger angle scales in elevation. In addition,a wireless positioning method based on single base station could be achieved by using a frequency driven scanning antenna.