A Dual-Polarized Endfire Antenna With Shared Aperture for mmWave Mobile Terminal Applications

This communication presents a novel compact wideband dual-polarized (DP) endfire antenna with a shared aperture. The design achieves a low-profile and wideband vertical-polarized (VP) element by utilizing an open-end cavity antenna with a U-slot and rectangular parasitic patch. A horizontal-polarized (HP) radiator is seamlessly integrated into the VP element by transforming the rectangular parasitic patch into a dipole, enabling structure reuse without affecting the VP mode. These designs enable the construction of a compact DP endfire antenna with a shared aperture while simultaneously enhancing performances, including impedance bandwidth, front-to-back ratio (FBR) level, polarization isolation, and cross-polarization. Moreover, a 1x4 -element array with high gain is designed based on the proposed element. Prototypes are fabricated using low-temperature co-fired ceramics (LTCC) technology for antenna-in-package (AiP) applications. As the simulated and measured results demonstrate, the antennas achieve a wide overlapped DP impedance bandwidth of 24-30 GHz (22.2%) and a low profile of 0.12 lambda(0). Specifically, the VP FBR levels surpass 14 dB (element) and 16 dB (array), while the port isolations exceed 30 dB (element) and 25 dB (array). Overall, this design presents a promising solution for high-integration mmWave mobile systems.