Since the complex coupling between end-fire antenna elements

high side lobe level is produced without high gain when the space of the end-fire antenna array is less than 1.5 . In order to restrain the coupling

the space of the array should be increased but the grating lobe is produced concurrently.For this reason

taking the 10-monopole plate end-fire antenna as the array element arranged with large spacing and virtual elements interpolated

an echo algorithm of virtual end-fire antenna array based on modified least squares estimation was put forward.Using this algorithm

the echo signals of virtual elements were obtained in order to restrain the grating lobe.And then

the far field patterns of the virtual end-fire antenna array were compared and analysed between results calculated by traditional least squares and modified least squares.With this understanding

it can be proved that the new algorithm has superiority over the traditional one and the validity in grating lobe restraining and side lobe reduction can be confirmed.