In this work, a mmWave planar substrate integrated waveguide Blass matrix is proposed. By utilizing a cruciform planar coupler, the normally two-layer beamforming network is reduced to a one-layer design, reducing complexity, while achieving similar performance to its two-layer counterpart. Simulated results show a 15 dB return loss for an operational bandwidth of 1 GHz (24.25 - 25.26 GHz) with an amplitude, and phase deviation less than 2.8 dB, and 10°, respectively.
