A planar dual-polarized microstrip 1D-beamforming antenna array for the 24GHz ISM-band

A planar dual-polarized patch antenna array with vertical beamforming capability is presented. The array is designed in terms of three horizontal rows consisting of ten elements each. They are fed in series transmission line architecture and the design frequency was chosen to 24.125GHz, which is the center of the 24GHz ISM-band. Each patch branch was matched against a 10-dB reflection-loss criterion. In the horizontal plane the array's directivity pattern is determined by the horizontal pattern of the respective rows. It exhibits a sidelobe level of less than −17 dB. This was achieved by appropriately tapering the amplitude distribution across all elements of a row. Radiated cross-polarization and isolation of the feed ports show accordingly good values. Inter-element space could be reduced to approximately 0.6 Λ0 in each row. The respective spacing between the rows is roughly on wavelength. The novelties and the potential of this dual-polarized antenna array are discussed in detail and its characteristics are brought forward by simulation and measurement results.