Broadband Waveguide Dual-Polarization Four-Way Power Divider for Small Passive Arrays

A waveguide dual-polarization four-way power divider is described. It relies on a novel, broadband, and compact offset twist design, enabling an output port spacing of about $0.7\lambda _{0}$ at the lowest operating frequency, which represents an improvement by approximately a factor of 2 over previously reported solutions with similar characteristics. With a highly integrated two-probe orthomode transducers (OMTs) and ${E}$ -plane T-junctions arrangement, the proposed device provides good matching to free space in a small array configuration of open-ended waveguides. The concept is detailed through a specific implementation in the ${K}$ -band, designed to operate over the frequency range of 17.7–20.2 GHz. The numerical model of the power divider alone achieves a frequency bandwidth up to about 3 GHz with a return loss better than 22 dB. Combined with an OMT for test purposes, the designed prototype demonstrates return loss better than 19 dB over the targeted bandwidth. This concept is of interest for the design of small passive array beamforming networks in the millimeter-wave band.