Package Substrate Patch Antenna Layout for Surface Wave Suppression
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Solution Overview
Problem
On-chip antennas operating in mm wavelength and THz frequency bands suffer from poor radiation efficiency due to ohmic losses, dielectric losses, and performance degradation from packaging materials, as well as interference from off-chip components, which affect directionality and overall radiation performance.
Innovation Solution
A multilevel package substrate with a ground structure surrounding the antenna, encapsulated by a molding compound, which includes a ground plane and dielectric layers to suppress surface wave modes and isolate the antenna from surrounding metal layers, enhancing radiation efficiency and directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If on-chip antennas are implemented in mm wavelength and THz frequency bands, then wireless communication functionality is achieved, but radiation efficiency deteriorates due to ohmic losses and dielectric losses
Solution Approach 1:
The patent transitions from planar 2D antenna structures to three-dimensional立体 ground structures that surround the antenna element. The ground structure extends in multiple directions (x, y, and z dimensions) to form a cage-like configuration, utilizing the third dimension to suppress surface wave modes and reduce dielectric losses that plague conventional planar antennas.
Solution Approach 2:
The patent introduces a dielectric layer with optimized properties as an intermediary between the antenna element and the ground structure. This intermediate dielectric layer acts as a mediator to control electromagnetic field distribution, reduce ohmic losses in metal layers, and minimize dielectric losses by selecting materials with appropriate loss tangents for the specific frequency band.
2Ease of manufacture
If planar antenna structures are used, then manufacturing is simplified, but radiation efficiency deteriorates due to surface wave mode generation
Solution Approach 1:
The patent employs three-dimensional ground structures that extend vertically and laterally to surround the antenna element, creating a cage-like configuration. This dimensional expansion effectively suppresses surface wave modes by providing additional current paths and increasing the electrical size of the ground structure, thereby reducing energy loss while remaining compatible with standard PCB fabrication techniques.
Solution Approach 2:
The patent utilizes composite structures combining multiple dielectric layers with different properties and metal patterns. The combination of low-loss dielectric materials with optimized ground structure configurations creates a composite system that suppresses surface waves while maintaining manufacturing feasibility through layered construction methods.
3Device complexity
If antennas are placed near off-chip components, then device integration is improved, but radiation performance deteriorates due to reflection and absorption of electromagnetic energy
Solution Approach 1:
The patent extracts or isolates the antenna element from the surrounding electromagnetic environment by surrounding it with a dedicated ground structure. This ground cage acts as a protective barrier that separates the antenna from nearby off-chip components, reducing electromagnetic interference, reflection, and absorption while allowing the antenna to maintain its radiation performance in integrated device configurations.
Solution Approach 2:
The ground structure serves as an intermediary barrier between the antenna and surrounding off-chip components. It mediates electromagnetic interactions by providing controlled reflection and shielding, thereby protecting the antenna from harmful reflections and absorptions while enabling close integration with other device components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly improves radiation efficiency and gain of mm wavelength and THz frequency antennas by suppressing surface wave modes and isolating the antenna from interference, resulting in improved directivity and communication performance.
Implementation Method 1
there is loss of radiated power to generated higher-order surface wave modes
Implementation Method 2
there is loss of radiated power to generated higher-order surface wave modes, which further limits the antenna radiation efficiency of planar structures. In addition, proximity to off-chip components can cause reflection and absorption of electromagnetic energy
Data Source
AI summary
An electronic device includes a multilevel package substrate, a semiconductor die, and a package structure, the multilevel package substrate has first, second, and third levels including respective dielectric layers and conductive features, the first level including a first trace layer with an antenna and a first via layer with a portion of a ground wall laterally spaced outward from and surrounding the antenna, and the second level including a second trace layer having a ground plane connected to the ground wall, the semiconductor die attached to the first level of the multilevel package substrate, and the package structure including a molding compound covering the semiconductor die and extending on a side of the antenna, where the package structure mold compound maters and thickness can be tuned for improved performance.