Millimeter-wave Multimode Beamforming Network Based on Double-ridged Waveguides

In this paper, a 4×4 compact beamforming network (BFN) operating from 26 to 34 GHz without phase shifters is proposed. The BFN is based on the fully metallic double-ridged waveguide technology, which can effectively expand the bandwidth and achieve the miniaturization. The BFN has four input ports and four output ports, and is designed by the scattering matrix (S-matrix) analysis. By switching the excitation of the input port, the phase difference of -140°, -50°, 50°, and 140° can be obtained. The simulated results show the beam scanning from -30° to 30° by loading the waveguide slot antennas, indicating the application potential in the millimeter-wave wireless systems.