A Multilayer Dual-Polarized Stacked Patch Antenna With Enhanced Port Isolation for mmWave Highly Integrated Applications

This paper introduces a dual-polarized stacked patch antenna for millimeter-wave (mmWave) antenna-in-package (AiP) applications, utilizing a multilayer stack-up consisting of 14 metallic layers. In order to ensure high port isolation even at large scan angles of ±60 degrees, a metallic isolation wall is introduced into the feed cavity. The prototyping process utilizes high density interconnect (HDI) technology due to its ability to create densely populated microvias. This paper details the working principle, design process, fabrication details, and measurement results of the antenna. The results demonstrate that the designed AiP operates in the frequency range of 24.25-27.5 GHz with an isolation of 28 dB between the ports within the antenna element. Additionally, the antenna exhibits stable radiation patterns and low cross-polarization levels of less than −19 dB over the operation bandwidth.