Microwave Antenna Coupling in eWLB Packages
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Solution Overview
Problem
Current microwave antenna packaging technologies, such as fan-out wafer level packaging, face limitations in operating bandwidth, radiation efficiency, and parasitic radiation due to thick mold compounds, which restrict their application in long-range and medium-range radar systems, and are costly due to the use of RF laminates for SIW-type transmission lines.
Innovation Solution
A microwave antenna coupling apparatus is designed with a mold layer, semiconductor and antenna coupling elements separated from the mold material, and a redistribution layer connecting them, allowing for separate integration of antenna modules on top of the package, enabling Package-on-Package (PoP) antennas with improved radiation efficiency and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If planar antenna structures are printed on redistribution layers in fan-out wafer level packages, then system integration is achieved, but operating bandwidth is limited to 1-5%
Solution Approach 1:
The patent transitions from planar 2D antenna structures printed on redistribution layers to three-dimensional antenna structures formed within the mold compound using through-mold vias and embedded conductors. This dimensional change enables broader operating bandwidth by creating vertical current paths and resonant structures that operate across multiple frequency bands, overcoming the inherent bandwidth limitations of planar designs.
2Reliability
If thick mold compound is used in the radiating direction for packaging, then component protection is improved, but radiation pattern is distorted
Solution Approach 1:
The patent incorporates antenna structures and conductive elements directly within the mold compound during the packaging process, before the mold compound cures and forms its final protective structure. This preliminary integration allows the antenna to radiate through optimized paths within the mold material itself, preventing the distortion that would occur if antennas were placed after packaging or required thick external mold layers for protection.
3Ease of manufacture
If planar antenna structures are used in fan-out packages, then manufacturing is simplified, but parasitic radiation to all directions increases
Solution Approach 1:
The patent employs localized ground planes, shielding structures, and directional antenna elements embedded within the mold compound at specific positions around the radiating elements. These locally optimized structures control the distribution of electromagnetic fields, directing radiation in desired directions while suppressing parasitic radiation to unwanted directions, thereby reducing interference without complicating the overall manufacturing process.
4Length of moving object
If additional apparatus is added to planar antenna structures to provide gain for long-range radar, then radar range is improved, but device complexity increases
Solution Approach 1:
The patent integrates antenna elements, feed networks, and gain-providing structures directly into the mold compound package, merging what would traditionally be separate components into a single integrated unit. The three-dimensional antenna structures embedded in the mold provide the necessary gain for long-range radar applications while maintaining a compact form factor, eliminating the need for additional external apparatus and reducing overall system complexity.
Data Source
AI summary
A microwave antenna coupling apparatus forming an eWLB package, comprises an antenna coupling element comprising a coupling unit, a coupling feed line arranged on a first surface of the coupling unit and an internal coupling component to provide signal coupling between the coupling feed line and the second surface of the coupling unit, wherein the antenna coupling element is arranged within the mold layer separate from the semiconductor element and such that an outer surface of the coupling feed line is not covered by mold material. Different multi-layer antenna structures can be placed on top of eWLB package. By this type of integration Package-on-Package (PoP) antenna are constructed. The elements can be integrated by a standard pick and place process.