Multilayer Antenna Substrate Layout for Ground Capacitance Control
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Solution Overview
Problem
Existing multilayer substrates with stripline structures face challenges in generating appropriate capacitance between the radiation conductor and the ground conductor, limiting their application in antenna devices due to the majority of the radiation conductor overlapping the upper ground conductor.
Innovation Solution
A multilayer substrate design with a stripline structure where the lower ground conductor serves as part of the antenna section, featuring a radiation conductor surrounded by an annular ground conductor, and signal line conductor, with specific positioning of interlayer connection conductors to minimize unwanted capacitance and coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmission line section has a stripline structure with the radiation conductor overlapping the upper ground conductor, then the antenna section can be constructed with stable radiation characteristics, but the lower ground conductor cannot serve as part of the antenna section and appropriate capacitance cannot be generated
Solution Approach 1:
The patent divides the ground conductor system into distinct functional zones: the upper ground conductor serves as a reference plane for the stripline transmission line, while the lower ground conductor is positioned to serve dual purposes as both a reference plane and as part of the antenna radiating structure. This segmentation allows each ground conductor to fulfill its specific function without interference.
Solution Approach 2:
The patent utilizes the vertical stacking dimension to resolve the contradiction. By positioning the lower ground conductor in a different vertical layer and configuring it to extend beyond the stripline structure, it can participate in radiation while the upper ground conductor maintains its transmission line function. This dimensional separation enables both functions to coexist.
2Reliability
If the radiation conductor is positioned to overlap the upper ground conductor for stable antenna construction, then the antenna section achieves reliable radiation characteristics, but the substrate thickness must be increased to accommodate the stripline structure
Solution Approach 1:
The patent merges the transmission line function and antenna radiation function into a single integrated structure. The lower ground conductor serves dual purposes: as a reference plane for the stripline transmission line and as part of the antenna radiating element. This merging eliminates the need for separate structures and reduces overall substrate thickness.
Solution Approach 2:
The lower ground conductor is designed with multi-functionality, serving both as a reference plane for electromagnetic signal transmission and as an active radiating element for antenna operation. This universal design allows the same component to fulfill multiple functions, reducing the number of layers required and thereby reducing substrate thickness.
3Manufacturing precision
If the lower ground conductor serves as part of the antenna section with the radiation conductor, then appropriate capacitance can be generated for desired frequency radiation, but the majority of the radiation conductor overlaps the upper ground conductor limiting application
Solution Approach 1:
The patent applies local quality by creating different functional regions within the ground conductor system. The upper ground conductor provides uniform reference plane properties for the transmission line, while the lower ground conductor is configured with extended regions that provide localized capacitance for frequency control and radiating properties for antenna operation.
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
This configuration allows for reduced thickness and improved capacitance between the radiation and ground conductors, enabling stable antenna performance without increasing the substrate's thickness, and supports various frequency bands and polarization types.
Implementation Method 1
it is not possible to generate an appropriate capacitance between a lower ground conductor thereof and the radiating element in order to achieve radiation characteristics at a desired frequency
Data Source
AI summary
A transmission line section of a multilayer substrate forms a stripline including an upper ground conductor, a lower ground conductor, and a signal line conductor. The antenna section includes a signal line conductor interlayer connection conductor that electrically connects the radiation conductor to the signal line conductor, and one or more ground conductor interlayer connection conductors that electrically connect an upper-surface annular ground conductor to the lower ground conductor and the upper ground conductor of the transmission line section. Viewed in the stacking direction of a plurality of base materials, the entire surface of the radiation conductor overlaps the lower ground conductor, and an end portion of the upper ground conductor is inside an annular shape formed by the upper-surface annular ground conductor at a position that overlaps the signal line conductor but does not overlap the radiation conductor.