Tunable Frequency Selective Limiter Using Electromagnetic Induction

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Solution Overview

Problem

Current magnetic frequency selective limiters are non-tunable and face challenges in miniaturization due to the nonlinear decrease of magnetic fields with size, limiting their ability to adjust frequency ranges and power thresholds, which is problematic for applications requiring dynamic adjustment and compact designs.

Innovation Solution

A tunable frequency selective limiter is developed, incorporating a ferrimagnetic layer, a dielectric layer, and a second conductive path that allows for adjustment of the magnetic field through electromagnetic current, enabling dynamic adjustment of frequency ranges and power thresholds, and is fabricated using microfabrication techniques for miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If magnetic frequency selective limiters are miniaturized, then device size is reduced, but magnetic field strength decreases nonlinearly

Engineering Contradiction:
Improvedevice sizeVSAvoidmagnetic field strength
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent applies parameter changes by transitioning from permanent magnets to electromagnets, allowing dynamic adjustment of magnetic field strength through electrical current control. This enables maintaining sufficient magnetic field strength in miniaturized devices while providing tunability of the frequency selective limiting characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/permanent magnetic system with an electromagnetic system. By using electromagnets instead of permanent magnets, the device achieves both miniaturization and controllable magnetic field strength through electrical actuation, resolving the nonlinear decrease of magnetic field with size reduction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If magnetic frequency selective limiters are made non-tunable, then device complexity is reduced, but adaptability to different frequency ranges and power thresholds is limited

Engineering Contradiction:
Improvedevice complexityVSAvoidfrequency range adjustment capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the magnetic field strength and frequency range tunable through electrical current control. The electromagnet allows dynamic adjustment of operating parameters, enabling the device to adapt to different frequency ranges and power thresholds while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent achieves universality by designing a tunable frequency selective limiter that can operate across multiple frequency ranges and power thresholds. The electromagnet-based design allows a single device to perform multiple functions by adjusting electrical parameters, eliminating the need for multiple fixed-frequency devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If traditional RF limiters are used, then protection from high power signals is provided, but signals from smaller desired signals are also reduced

Engineering Contradiction:
Improveprotection from high power signalsVSAvoidsignal to noise ratio
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by creating frequency-selective attenuation characteristics. The frequency selective limiter provides strong attenuation only for high power signals at specific frequencies while maintaining transparency for lower power desired signals, achieving localized protection without degrading overall signal quality.

Inventive Principle:
Principle #3Local quality

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 tunable frequency selective limiter effectively attenuates RF signals across a range of frequencies and power thresholds, providing a compact and adjustable solution for RF signal management, enhancing protection of sensitive equipment while allowing for miniaturization and dynamic adjustment.

Implementation Method 1

A tunable frequency selective limiter includes a ferrimagnetic layer, a dielectric layer, and a second conductive path

Methodology Applied
Scientific EffectMagnetic resonance: Resonance

Implementation Method 2

a second conductive path that allows for adjustment of the magnetic field through electromagnetic current

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

The permanent magnet is further configured to set a fixed magnetic bias on the tunable frequency selective tuner

Methodology Applied
Scientific EffectMagnetic bias: Magnetic Field

Data Source

PatentEP3771027B1Tunable frequency selective limiter
Publication Date: 2023.06.28 ROCKWELL COLLINS INC
  • EP3771027B1 patent drawingFigure 1
  • EP3771027B1 patent drawingFigure 2
  • EP3771027B1 patent drawingFigure 3

AI summary

A tunable frequency selective limiter is disclosed. In one or more embodiments, the tunable frequency selective limiter includes a first electrically conductive path (110). The tunable frequency selective limiter also includes a ferrimagnetic layer (120) disposed adjacent to the first electrically conductive path. The tunable frequency selective limiter further includes a second electrically conductive path (140) coiled around the first electrically conductive path and the ferrimagnetic layer. An electromagnetic current transmitting through the second electrically conductive path produces a magnetic field coupled to the ferrimagnetic layer. The tunable frequency selective limiter further includes a dielectric layer (130), wherein the ferrimagnetic layer is disposed on the dielectric layer. The portions of the second electrically conductive path that are at the interface of the dielectric layer and the ferrimagnetic layer may be embedded into the dielectric layer or may be disposed on the surface of the dielectric layer.