Direction finding based on plane wave spectrum transform

To deal with the multiple-path direction finding problem, a new arithmetic based on the plane wave spectrum transform is presented. The theory and practice of planar near-field measurement have been examined; its principle of plane wave spectrum transform can not only be used in microwave anechoic chambers, but can also be used in free space. The paper mainly discusses the application of the plane wave spectrum transform in direction finding in terms of finite incident waves, and the relationship between the resolving power of the wave spectrum and the geometry of the plane antenna array that is used in direction finding. Furthermore, the paper analyzes a new expanded antenna array method to estimate the multiple signals´ directions-of-arrival (DOA) on a more accurate level.