A planar dual-polarized microstrip antenna array in series-parallel feed configuration

A novel concept for a dual-polarized microstrip antenna array with a center frequency of 23.75 GHz is introduced. The array is composed of ten single square patch elements having equal resonance frequencies in both directions. The microstrip patches are rotated by 45 ° and linearly aligned to obtain a fan beam antenna characteristic. The feed structure is in seriesparallel configuration with best advantages in space saving. The antenna array is fully planar and compact but has nevertheless a very low cross-talk between its two orthogonal channels of <; -30 dB. The sidelobe level (SLL) of the antenna array is decreased to -16.8 dB by implementing an amplitude taper according to Dolph-Chebyshev (DC). The main beam direction for both polarizations of the antenna array is boresight, with a half-power beamwidth (HPBW) of 10 ° for φ = 0° and 100 ° for φ = 90°. By using an array of these fan beam antenna arrays, one-dimensional beamforming applications can be realized. Due to its high polarization purity, low sidelobe level and fan-beam characteristics, the antenna array can be used in 5G mobile applications.