Integration Design of Millimeter-Wave Filtering Patch Antenna Array With SIW Four-Way Anti-Phase Filtering Power Divider

In this paper, the integration design of a millimeter-wave filtering patch antenna array fed by a substrate integrated waveguide (SIW) four-way anti-phase filtering power divider is proposed. The multilayer four-way anti-phase filtering power divider handily implemented using the intrinsic field distribution of TE₂₀-mode in SIW is proposed for miniaturization. The signal of the lower substrate integrated waveguide cavity (SIWC) bandpass filter is directly coupled to the upper TE₂₀-mode SIW through a coupling slot. The intrinsic field distribution of TE₂₀-mode SIW is used to generate anti-phase signals. This filtering power divider can be utilized as the feeding structure of a millimeter-wave filtering antenna array. To verify the design concept, a 28-GHz SIW-fed 1 × 4 filtering patch antenna array with three-layer substrates is designed and fabricated. The measured results show a fractional bandwidth of 5.03% ranging from 27.15 to 28.55 GHz, a peak gain of 11.1 dBi, cross-polarization levels lower than -20 dB, symmetric radiation patterns in both E-plane and H-plane, and high selectivity.