Slotted Reference Conductor Filter for Absorbing EMI Noise

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Solution Overview

Problem

Conventional filters, particularly reflective filters, struggle to effectively absorb electromagnetic noise at specific frequencies, leading to ongoing electromagnetic interference (EMI) and radio frequency interference (RFI) issues in high-speed data transmission systems.

Innovation Solution

The proposed solution involves an equivalent filter circuit and a filter device that utilize multiple equivalent transmission line models and impedance units. These components are configured in series, parallel, or series-parallel arrangements to absorb noise at specific frequencies. The filter device features a substrate with a transmission conductor and a slotted reference conductor, where impedance units are strategically placed to enhance noise absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional reflective filter is used, then the noise is reflected back to the original path, but the reflected common-mode signal may be transmitted to other radiating elements causing electromagnetic interference to persist

Engineering Contradiction:

Improveelectromagnetic interferenceVSAvoidnoise suppression effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent inverts the conventional reflective filter approach by using an absorptive filter instead. The filter device absorbs common-mode noise signals through impedance matching and resistive elements, converting the harmful reflected noise into heat energy, thereby preventing the noise from being transmitted to other radiating elements.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful noise energy into beneficial heat energy through the use of resistive elements and impedance matching networks. The common-mode noise signals are absorbed and dissipated as heat, transforming the harmful electromagnetic interference into a harmless thermal effect.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Speed

If the signal transmission speed is increased for high-speed data transmission, then data transmission rate improves, but electromagnetic noise and interference are generated more easily

Engineering Contradiction:

Improvesignal transmission speedVSAvoidelectromagnetic noise

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary filter device between the high-speed signal transmission path and the surrounding environment. This filter device acts as a mediator that allows the high-speed signal to pass through while absorbing and blocking the electromagnetic noise generated by the fast transitions, thus protecting other radiating elements from interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a simple filter structure is used, then device complexity is reduced, but the filter cannot effectively absorb noise at specific frequencies

Engineering Contradiction:

Improvefilter structure complexityVSAvoidnoise absorption capability

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent employs parameter changes in the form of adjustable impedance values and resonant frequencies within the filter device. By varying the impedance of the resistive elements and the resonant frequencies of the LC circuits, the filter can be tuned to effectively absorb noise at specific frequency ranges while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure combining resistive elements, inductive elements, and capacitive elements in an integrated filter device. This composite approach allows the filter to exhibit both absorptive and frequency-selective characteristics, achieving effective noise absorption at specific frequencies without requiring a overly complex structure.

Inventive Principle:

Principle #40Composite materials

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 described technical solution effectively absorbs electromagnetic noise at specific frequencies, thereby reducing EMI and RFI in high-speed data transmission systems, leading to improved signal quality and reduced interference.

Implementation Method 1

A capacitive coupling effect generated between the transmission conductor and the slotted structure can be increased by the configuration of the second reference conductor

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS12206148B2Filter device and equivalent filter circuit thereof

Publication Date: 2025.01.21 NAT TAIWAN UNIV

AI summary

The invention discloses a filter device. The filter device comprises a substrate, at least one transmission conductor, and a reference conductor having a slotted structure. The substrate is provided at a first surface thereof with the transmission conductor, and provided at a second surface thereof with the reference conductor. The slotted structure comprises a frame portion, a slotted portion, and a hollow portion. The slotted portion surrounds the frame portion, and the hollow portion is formed in the frame portion. At least one impedance unit is configured on the frame portion. The equivalent filter circuit of the filter device is formed between the transmission conductor, the slotted structure, the reference conductor, and the impedance unit. Thereby, the equivalent filter circuit absorbs at least one noise at at least one specific frequency by the impedance unit to avoid the noise reflected to affect the transmission quality of signal.