A Scalable X-Band Overlapped Subarray Beamformer for Linear Phased Array Antennas

In this work, overlapped subarray architecture is proposed to create multi-beams at the same time with using independent receiver subarrays with high isolation which are fed from the same antenna elements and it reduce to required number of antennas compared to conventional subarrays. A periodic structure is created with using identically designed sub-array PCB's and the scale of the system can be adjusted with that periodic structure. Since the sub-array design depends on the antenna spacing, it has a scalable structure for different frequencies. Due to the overlapping sub-array structure, the distance between sub-arrays is less than conventional and it reduces the negative effects such as a high sidelobe and grating lobe of the subarray method. With the proposed architecture, each antenna element is connected to 3 subarrays to create a 3 to 1 overlapping structure and the output of the sub-arrays can be combined with using a power combiner to reduce the number of outputs. To implement this structure, a 12-element linear antenna array and a subarray beamformer were designed and manufactured. The antenna array designed as parasitic patch structure to increase the frequency band that can scan ±50 degrees. The subarray beamformer is designed as a multilayer PCB to overcome the crossover that occur while overlapping the elements.