Design of a mm-Wave Double-Sided Substrate Blass Matrix Beamforming Network

This work presents a multilayer Blass matrix architecture for mm-Wave applications. Three main problems of the original Blass matrix are tackled with the proposed topology. First, the spurious excitation problem, which is caused by multiple signal paths and degrades the matrix performance, is reduced. Second, our design approach ensures the design of a Blass matrix with the minimum possible losses. Third, directional slot couplers are designed eliminating the crossovers. The proposed design shows a remarkably constant phase difference in the K a frequency band.