Multi-Antenna-in-Package with High Isolation

A millimeter-wave antenna system with a compact structure and high isolation is investigated in this paper. Three patch antennas are integrated into a limited space ($1.2 \cdot \lambda_{0} \times 1.2 \cdot \lambda_{0}$). The fundamental TM 01 mode of the patch antenna is excited by a probe. The common bandwidth of these patches is from 23.5 to 24.4 GHz (3.76%). In the operation band, high isolation can be guaranteed by rotating the patches by 45° and introducing an X-shaped decoupling structure. With these features, the system is suitable for integration with chips and it can be applied to Antenna-in-Package (AiP). Therefore, it has promising applications in radar sensing, ranging, and positioning.