A Two-Dimensional 6×4-Way Hollow Waveguide Beam-Switching Matrix

This paper presents a design of a two-dimensional (2-D) $6\times 4$ -way hollow waveguide beam-switching matrix working at 28.25 GHz, with a fractional bandwidth of 7.1%. It is the first time that a 2-D one-body hollow waveguide beam-switching matrix is proposed with different number of beams in two orthogonal directions. This matrix is partially adopting two-plane couplers to reduce its overall dimensions. A prototype of the complete matrix is manufactured and measured using a planar scanning near-field setup to verify the simulation results. At the center frequency of 28.25 GHz, the highest directivity is obtained for the beam having the smallest tilting angle, with a value of 21.1 dBi in simulation and 21.3 dBi in measurement. The lowest directivity corresponds to the beam having the largest tilting angle, with a simulated value of 16.0 dBi and a tilting angle of 52° from the boresight, which represents a worst-case scan loss of 5.1 dB. The measured value is overestimated in that specific case, as a consequence of the truncation in the planar near-field test setup which has higher impact on the most tilted beams. The patterns are nevertheless in good agreement and the proposed matrix is a good candidate for applications requiring a different beam distribution in two orthogonal directions.