A W-band sparse phased array antenna with ultrahigh sparsity for radar applications

A sparse phased array with 4% sparsity is developed for advanced low-cost W-band radar applications. A high-order radiation mode-based substrate-integrated waveguide antenna featuring waveguide feeding is employed as the antenna element to achieve feeding loss reduction and antenna gain enhancement. An improved optimization technique is adopted to optimize the antenna element distribution. The combination of the element distribution and the antenna element radiation pattern achieves grating lobe suppression. Both the simulation and measurement results show that a +/- 15 degrees beam scanning range can be achieved, and the level of the measured normal and scanning sidelobes is lower than -18 dB and -13 dB, respectively.