A High-Gain Series-Parallel Millimeter-Wave SIW Cavity-Backed Patch Array

This paper presents a wideband and high-gain 4 × 4 substrate integrated waveguide (SIW) cavity-backed patch array with a simplified feeding network for operation in the millimeter-wave (mmW) band. Furthermore, to improve gain and suppress the sidelobe level, a stepped waveguide horn is vertically integrated with each SIW cavity-backed patch. The proposed 4 × 4 array comprises eight series of 2 × 1 subarrays and a simplified 4-way power distribution network. In addition, two types of series-parallel 4 × 1 subarrays are examined to achieve a low sidelobe level. For verification, the proposed 4 × 4 antenna array was fabricated and measured, with the results showing good agreement with the simulations. The fabricated array prototype realized a -10 dB impedance bandwidth of 14.7% in the 24–27.8 GHz frequency band, with a peak gain of 22.05 dBi. Overall, based on its advantages—wide band, high gain, low cost, and compact feeding network—the proposed array can be considered a potential candidate for use in mmW wireless applications.