Compact EBG Structure via Open Stub and Slit
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Solution Overview
Problem
Conventional EBG structures for suppressing electromagnetic noise are too large and ineffective for high-frequency bands used in modern electronic devices, such as those in wireless LAN and LTE, due to their size and parasitic inductance limitations.
Innovation Solution
A compact EBG structure is achieved by incorporating a first and second conductor plane with a first transmission line acting as an open stub and a slit on the second conductor plane, functioning as an inductance imparting member, to create a return path for the transmission line via a conductor via, thereby reducing the size and enhancing noise suppression capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional EBG structure is used to suppress electromagnetic noise, then noise suppression is achieved, but the structure becomes large in size
Solution Approach 1:
The EBG structure is divided into unit structures that are periodically arranged. Each unit structure contains a transmission line connected between conductor planes and a slit formed on one of the conductor planes. This segmentation allows the noise suppression function to be distributed across multiple small units rather than requiring one large structure.
Solution Approach 2:
The patent utilizes the third dimension (vertical direction) by forming transmission lines that extend between conductor planes stacked in the vertical direction. This allows the EBG structure to achieve noise suppression in a compact horizontal footprint by utilizing vertical space for the transmission line paths.
2Object-affected harmful factors
If a decoupling capacitor is used to suppress electromagnetic noise, then noise suppression is achieved at low frequencies, but it becomes ineffective at high frequencies due to parasitic inductance
Solution Approach 1:
The patent replaces the electrical component approach (decoupling capacitors) with a structural electromagnetic approach (EBG structure using conductor planes and slits). This structural approach creates a frequency band gap through geometric configuration rather than relying on component characteristics, eliminating the parasitic inductance problem inherent in capacitor-based solutions.
Solution Approach 2:
The patent changes the fundamental parameter from component value selection (capacitor capacitance) to geometric dimensioning (transmission line length, slit dimensions, conductor plane spacing). By controlling the physical dimensions of the transmission lines and slits, the EBG structure achieves frequency-selective noise suppression without being limited by parasitic inductance.
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 proposed structure effectively suppresses electromagnetic noise across high-frequency bands, enabling miniaturization while maintaining effective noise blocking characteristics, thus improving circuit stability and radio performance in electronic devices.
Implementation Method 1
a first transmission line that is formed in a layer different from the first conductor plane and the second conductor plane and is disposed so as to face the second conductor plane, one end of the first transmission line being an open end; a conductor via that connects another end of the first transmission line with the first conductor plane
Implementation Method 2
a slit that is formed on the second conductor plane and stretches to both sides of the first transmission line from a starting point where the slit overlaps the first transmission line in a plan view
Data Source
AI summary
Provided is a structure including at least: a first conductor plane; a second conductor plane disposed so as to face the first conductor plane; a first transmission line that is formed in a layer different from the first conductor plane and the second conductor plane and is disposed so as to face the second conductor plane, one end of the first transmission line being an open end; a conductor via that connects another end of the first transmission line with the first conductor plane; a slit that is formed on the second conductor plane and stretches to both sides of the first transmission line from a starting point where the slit overlaps the first transmission line in a plan view. Thus, a structure that enables formation of a compact EBG structure is provided.