This paper focuses on characterizing the evolution of warpage, effects of epoxy molding compound (EMC), and effects of carrier 2 (the second carrier in the process) of 12 inch RDL-first multi-die fan-out wafer-level packaging (FOWLP) during the manufacturing process. The linear viscoelasticity properties of EMC and polyimide (PI) were characterized using dynamic mechanical analysis (DMA) in the frequency domain at different temperatures., The elastic and viscoelastic model were used for PI and EMC, the finite element analyses (FEA) of the cured structure were carried out and the results were compared with the test results. The viscoelastic properties of the EMC in the FEA could predict the wafer warpage more accurately. The FEA and experiments were used to investigate the evolution of warpage. The molding had a great influence on the warpage. The effects of the EMC and carrier 2 were also investigated with FEA. The wafer warpage could be reduced by lowering the thickness of the EMC, increasing the thickness of carrier 2, and selecting EMC and carrier 2 with a matched coefficient of thermal expansion (CTE).

In this letter, a broadband high gain array antenna is loaded with parasitic patches is introduced. To achieve the wideband impedance matching, three parasitic patches stacked above the driven patch are proposed. The overall measurement of the proposed antenna is 4.6 λ0 × 4.6 λ0 × 0.092 λ0 (λ0 is the free-space wavelength at 94 GHz). Butterfly-shaped gaps and compact 2 × 2 power splitters are utilised due to the low wavelength of W-band. According to the measurement, the proposed antenna has a broad bandwidth, with |S11|<-10 dB of 26.59% from 85.2 to 110 GHz. In the 87-103 GHz band, the gain of the 8 × 8 array antenna is more than 22.2 dBi, and its gain fluctuation is less than 1.8 dBi across the whole operational frequency range. The measured E- and H-plane radiation patterns are stable across the operating band with sidelobe and cross-polarization levels below -25 dB and -30 dB, respectively.

This article presents a novel cross-rib micro-channel (MC-CR) heat sink to make fluid self-rotate. For a thermal test chip (TTC) with 100 w/cm², the cross-ribs micro-channel were compared with the rectangular (MC-R) and horizontal rib micro-channel (MC-HR) heat sinks. The results show that, with the cross-rib micro-channel, the junction temperature of the thermal test chip was 336.49 K, and the pressure drop was 22 kPa. Compared with the rectangular and horizontal ribs heat sink, the cross-rib micro-channel had improvements of 28.6% and 14.3% in cooling capability, but the pressure drop increased by 10.7-fold and 5.5-fold, respectively. Then, the effects of the aspect ratio (λ) of micro-channel in different flow rates were studied. It was found that the aspect ratio and cooling performance were non-linear. To reduce the pressure drop, the inclination (α) and spacing (S) of the cross-ribs were optimized. When α = 30°, S = 0.1 mm, and λ = 4, the pressure drop was reduced from 22 kPa to 4.5 kPa. In addition, the heat dissipation performance of the rectangular, staggered fin (MC-SF), staggered rib (MC-SR) and cross-rib micro-channels were analyzed in the condition of the same pressure drop, MC-CR still has superior heat dissipation performance.

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A full W-band antenna-in-package (AiP) array implemented in a six-layer high-density interconnect (HDI) package is presented. The radiator is a coplanar magnetoelectric (ME) dipole in which the electric dipole current and the equivalent magnetic current are synchronously excited on the same layer by a TM₁₀-mode coupling patch. Unlike previously reported slot-based via-free ME dipoles using a resonant λ₀/2 ground slot, the proposed magnetic source is a localized subwavelength gap, which suppresses vertical phase detuning and avoids electrically long-slot behavior at the upper W-band. A dual-layer artificial magnetic conductor (AMC) is further embedded as both an in-phase reflection boundary and a functional copper-density compensation structure for multilayer fabrication. Based on the proposed element, an 8×8 array is designed and fabricated. Measurements show an impedance bandwidth of 75–110 GHz (37.8%), a peak realized gain of 22.7 dBi, and stable symmetric broadside radiation across the full W-band. The proposed architecture is well suited for compact W-band HDI-AiP systems.

This letter presents a tri-mode magneto-electric (ME) dipole antenna based on high-density-interconnect (HDI) technology, offering high integration capability and manufacturability for W-band applications. The proposed antenna achieves broadband operation through tri-mode excitation of electric and magnetic dipole resonances, ensuring stable radiation performance across the band. Two array prototypes are fabricated and tested: a 2 × 2 parallel-fed array, demonstrating a measured bandwidth of 37.1% (75–109.2 GHz) and peak gain of 14.05 dBi; and a 1 × 8 series-fed array exhibits a measured gain of 14.83 dBi and a sidelobe level (SLL) of −15.78 dB at 77 GHz. This letter presents a promising pathway for scalable, broadband, and low SLL antenna-in-package integration at W-band.