This paper presents a comprehensive co-design approach for dielectric resonator antenna (DRA)-based Antennain-Packaging (AiP) solutions utilizing Fan-out Wafer Level Packaging (FOWLP) technology. Despite the advantages of highprecision wafer-level fabrication and advanced integration capabilities with multiple redistribution layers, traditional planar antenna-based AiP structures are often unsuitable for FOWLP due to potential warpage caused by the heating processes. In contrast, DRAs offer high radiation efficiency and effective warpage control through strategic sizing of the radiator and the distribution of dummy antenna dielectrics within the module. We evaluate the robustness of the proposed AiP design against fabrication errors through rigorous electromagnetic (EM) simulations, providing comprehensive design guidance. To mitigate the effects of antenna die misplacement, we employ symmetrical feeding techniques. This dual-feed configuration not only enhances the antenna's resistance to die shift but also allows for greater pattern diversity. We discuss an optimal dimension ratio that addresses thermo-mechanical issues while enabling dual-mode operation through proper excitation of higher-order modes TE x δ13 and TE x δ21. The proposed antenna was fabricated using a 6-inch FOWLP process, achieving a wafer-level warpage of less than 0.5 mm. Measured peak realized gain of 7.38 dBi for broadside radiation patterns and 6.1 dBi for monopole patterns were obtained at 140 GHz. The effectiveness of the FOWLP AiP concept has been validated through experimental results, demonstrating its potential applications in mmWave communication and radar systems.

This paper investigates near-field spot beamfocusing (SBF) using holographic antennas for multiuser communication applications. While far-field holographic surfaces have been widely explored, a comprehensive study of nearfield holographic surfaces, especially for precise beam-focusing, remains limited. In this work, we derive a closed-form analytical solution for the focal gap, enabling precise beam-focusing at the intended focal point. We characterize key physical parameters of near-field holographic antennas, including the depth of focus (DoF), angular beamwidth, and the effects of surface impedance quantization. Additionally, we introduce an interference cancellation algorithm that leverages orthogonal beam patterns on the focal plane, enhancing secure communication in multiuser scenarios. Extensive EM simulations and experimental measurements validate the proposed methods, demonstrating effective beam-focusing and interference mitigation for singleand multiuser applications. The results suggest that holographic SBF could be a pivotal technology for next-generation 6G wireless networks, offering significant potential for applications in secure communication, wireless power transfer, and medical technologies.