Slotted Ground Electromagnetic Noise Filter with Impedance Elements
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Solution Overview
Problem
Current electromagnetic noise filter devices are ineffective at high frequencies due to rapid permeability attenuation of electromagnetic materials and are costly to produce, limiting their application to low frequency ranges.
Innovation Solution
An electromagnetic noise filter device with a slotted ground structure and multiple pairs of impedance elements, including resistors, capacitors, or inductors, configured between a reference metal plane and a ground plane, which absorbs electromagnetic noise energy, reducing device size and enabling operation across multiple frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic material is used to suppress EMI, then EMI suppression effect is improved, but the permeability attenuates quickly at high frequency making it unsuitable for GHz range
Solution Approach 1:
The patent changes the fundamental parameter from relying on electromagnetic material permeability to using impedance elements (resistors, capacitors, inductors) with specific impedance values. This allows the filter to maintain effectiveness at high frequencies where traditional electromagnetic materials fail, as the impedance elements can be designed to provide the required filtering effect without suffering from permeability attenuation.
Solution Approach 2:
The patent replaces the mechanical/electromagnetic material-based EMI suppression mechanism with an electrical circuit-based mechanism using impedance elements. Instead of relying on the physical properties of electromagnetic materials, the solution uses equivalent filter circuits with resistors, capacitors, and inductors to achieve the same EMI suppression function, enabling operation at GHz frequencies.
2Reliability
If LTCC/HTCC multi-layered filter device is used, then EMI suppression effect is acceptable, but fabrication cost is extremely high and frequency range is limited to low frequency
Solution Approach 1:
The patent employs standard impedance elements (resistors, capacitors, inductors) that can be manufactured using conventional PCB techniques rather than expensive LTCC/HTCC processes. These components are widely available, cost-effective, and can be implemented as surface-mount devices or integrated into the PCB layout, dramatically reducing fabrication costs while maintaining EMI suppression effectiveness.
Solution Approach 2:
The patent creates a universal filter structure using standard impedance elements that can be applied across different frequency ranges and applications. The equivalent filter circuit design is not limited to specific frequency bands and can be adapted to various EMI filtering needs, making it more versatile and cost-effective than specialized LTCC/HTCC solutions.
3Reliability
If single pair of impedance elements is used, then EMI suppression at specific frequency is achieved, but multiple frequency transmission capability is limited
Solution Approach 1:
The patent divides the filtering function into multiple segments by using multiple pairs of impedance elements, each tuned to suppress EMI at different frequency ranges. This segmentation allows the filter to handle multiple frequency transmissions simultaneously, as each impedance element pair targets specific frequency bands while working together to provide broad-spectrum EMI suppression.
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 filter device effectively absorbs electromagnetic noise across various frequencies, preventing signal interference and improving transmission quality, with over 90% energy absorption at specific frequencies, and is cost-effective compared to previous technologies.
Implementation Method 1
an electromagnetic coupling generated on an electromagnetic noise filter device
Implementation Method 2
the impedance elements are adopted for absorbing the energy of the electromagnetic noise
Data Source
AI summary
The present invention is related to an electromagnetic noise filter device and an equivalent filter circuit thereof. The filter device comprises a substrate, a transmission line and a ground plane having slotted ground structure. The transmission line is configured on the top surface of the substrate, and the grounding plane is configured on the bottom surface of the substrate. At least one pair of impedance elements are configured within the slotted ground structure. The transmission line can be electromagnetic coupled to the slotted ground structure and the impedance elements so as to form an equivalent filter circuit. Thereby, the electromagnetic noises on at least one specific frequency may be absorbed by the impedance elements of the filter device so as to avoid the electromagnetic reflection induced by the electromagnetic noise and interfering the signal transmitted on the transmission line.