A Slot-Coupling Stacked Patches Antenna in Package for a 64-Elements W-Band Phased Array

This letter proposes a compact W-band antenna-in-package design for a phased array front-end module. A slot-coupled stacked patches structure is developed to address integration challenges and enhance bandwidth limited by the thin substrate. The antenna is optimized by particle swarm optimization algorithm and manufactured by cost-effective modified semiadditive process. Experimental results from an 8 × 8 phased array module demonstrate consistent performance, including $\pm 30^{\circ }$ beam scanning ability, low scan gain loss ($\rm < $ 2 dB), and low cross-polarization ($\rm < $ $-$20 dB) with a maximum measured effective isotropic radiated power (EIRP) of 54.8 dBm. This work provides a scalable and cost-effective solution for the integration of millimeter-wave phased array systems.