A low-cost implementation and a simplified digital signal control and synchronization for a multi-beam phased-array antenna is proposed. In a preferred embodiment, the multi-beam phased array antenna is implemented with a stack-up comprises 1) an antenna substrate aperture containing embedded antenna elements and a third layer of the signal combiner/divider and distribution network, 2) interposer substrate providing a second layer of the signal combiner/divider and distribution network and the carrier of BPU ICs, and 3) the BPU ICs containing the plurality of phased-array frontend processing unit and a first layer of the signal combiner/divider and distribution unit. In one advantageous aspect, the invention is to combine the third layer of the signal combiner/divider and distribution network with the antenna onto the same substrate, eliminating the use of expensive miniature high frequency connectors.