28–32 GHz Dual-Polarized Single-Layer Microstrip Line Beamforming Network for 2×2 Beam Switching

A 2×2 dual-polarized passive analog beamforming network is presented for millimeter-wave application in the range of 28-32 GHz. Two identical 2×2 networks, one for each polarization (H and V) are integrated on a single substrate layer. Highly isolated crossover is used to cross the RF signal for each polarization. To avoid spurious radiation, the microstrip line circuit is packaged with the AMC. The beamforming network has four beam-ports for each polarization. Therefore, eight beams can be generated, simultaneously. The 90°hybrid couplers are used to achieve 2D progressive phase shift at two stages. The transmission of -6.5 ± 0.25 dB is achieved from the beam-ports to the array-ports. Similarly, the progressive phase shift of 90°± 5° is achieved in X and Y direction.