Focused Array Antenna Using Subarrays

Array antennas are used in near-field-focused (NFF) applications recently. Typically Focused Array Antennas (FAA) are fed by multi-level power dividers. However, when it comes to large array antennas, the design of dividers is complicated, especially for tightly arranged arrays; also a large divider may cause large inserting loss when we use low-cost materials. A novel method is proposed in this paper to simplify the feeding network of a large FAA; subarrays are used and the array is fed on the subarray level, and the required phase distribution is realized by subarray geometry as well as the simplified divider. A 4 x 16 FAA working at 10 GHz with a focal distance 250mm is explored, simulated results show the new array has almost the same performance on the focal plane compared to its conventional counterpart and has no forelobe along the axial line.