Design of a shared arm slot array for imaging radar applications

In this paper, a shared arm slot array is designed and its performance investigated for use in imaging radar. In constructing a physical array structure for near-field target sensing, spacing antenna elements may become problematic owing to the limited antenna spacing constraint for alias-free sampling in the aperture domain. The proposed shared arm slot array is designed such that two slot elements share a single slot arm, thereby achieving an alias-free sampling. In this paper, as a proof-of concept, a simplified 2-port array is designed, and its characteristic in radiation pattern is compared with a slot antenna, whose length of an arm is the same as the proposed 2-port array. Since the initial array shows a radiation pattern distortion, the geometry is modified to reduce the surface current at the unwanted slot arm. As a result, the modified array shows a corrected radiation pattern, allowing the structure to be useful in imaging radar applications.