EBG Unit Cells with Interdigital Electrodes for High-Frequency Noise Isolation
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Solution Overview
Problem
Conventional printed wiring boards struggle to effectively isolate high-frequency noise from digital circuits, which can interfere with analog circuits, particularly in compact designs like portable devices, due to the size and complexity of existing EBG structures and the difficulty in balancing noise reduction with DC power supply.
Innovation Solution
A compact EBG structure is implemented with periodically arrayed two-dimensional or one-dimensional IDE-EBG unit cells on the power supply layer, featuring an interdigital electrode and a magnetic body film, which enhances capacitance and noise blocking capabilities without increasing size or complexity, allowing for efficient noise isolation across specific frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid patterns are used on power supply and GND layers, then DC power supply is stabilized, but high-frequency noise from digital circuits is transmitted to analog circuits
Solution Approach 1:
The power supply layer is segmented into multiple isolated EBG unit cells with periodic structures, creating electromagnetic bandgaps that block high-frequency noise while maintaining DC power supply through the insulating layer's conductive paths
Solution Approach 2:
The EBG unit cells are strategically positioned between digital and analog circuits to provide localized noise filtering, with each cell having specific geometric parameters optimized for blocking high-frequency components while allowing DC passage
2Object-affected harmful factors
If EBG unit cells with size of about 16.5 mm per side are used for noise block in 2.5 GHz band, then high-frequency noise is blocked, but the structure becomes too large for portable devices
Solution Approach 1:
The geometric parameters of the EBG unit cells (such as slot dimensions, conductor trace widths, and cell spacing) are optimized to achieve the desired 2.5 GHz noise blocking frequency with a significantly reduced physical footprint suitable for portable devices
Solution Approach 2:
The EBG structure utilizes the periodic arrangement in two dimensions with optimized unit cell geometry to achieve compact size, transforming the noise blocking function from a large-area planar structure to a compact periodic pattern
3Object-affected harmful factors
If slits are formed in the solid pattern to create EBG structure, then high-frequency component transmission is reduced, but DC power supply is disrupted when pattern is completely separated
Solution Approach 1:
The insulating layer serves as an intermediary medium between the segmented power supply layer and GND layer, providing conductive paths for DC power while the EBG unit cells in the conductor layer block high-frequency noise transmission
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 effectively blocks high-frequency noise within a desired frequency range, enabling compact designs that maintain reliable DC power supply and noise reduction, suitable for portable devices, by optimizing the EBG unit cell size and interdigital electrode configuration.
Implementation Method 1
an electromagnetic band gap (hereinafter, 'EBG') structure has an ability to reduce propagation of electromagnetic waves in a specific frequency band
Implementation Method 2
featuring an interdigital electrode and a magnetic body film, which enhances capacitance and noise blocking capabilities
Implementation Method 3
an electromagnetic band gap (hereinafter, 'EBG') structure has an ability to reduce propagation of electromagnetic waves in a specific frequency band
Implementation Method 4
EBG unit cells are periodically arrayed on a boundary between the digital circuit and the analog circuit one-dimensionally or two-dimensionally, and an interdigital electrode is formed
Data Source
AI summary
A printed wiring board includes a digital circuit, an analog circuit, and a power supply path that is disposed on an insulating layer between the digital circuit and the analog circuit. EBG unit cells are disposed on a boundary between the digital circuit and the analog circuit one dimensionally or two dimensionally and periodically, and an interdigital electrode is formed. A magnetic body film is formed over the printed wiring board, partially formed on the EBG unit cells, or formed avoiding the EBG unit cells.