A Virtual Subarray Architecture for Imaging Radar

In this paper, an architecture for imaging systems employing a smart subarray design to reduce the number of control points as much as possible is proposed. The radar consists of two linear arrays, orthogonally orientated to achieve the same response of a full planar rectangular array, while the feeds are realized by means of properly designed subarrays, that cancel out the grating lobes of the array factor. In the proposed architecture, the role of the subarrays is interchanged: The subarray that cancels out the grating lobes of the vertical array is used as the element of the horizontal array, and vice-versa, so that there is no feed overlapping. A synthesis strategy for the optimization of subarray and array excitations, based on generalized alternate projections, is also presented and validated by means of a number of simulations. The proposed radar is compared with other existing radar architectures, showing good performances with a very limited number of control points.