Orthogonal Coil Antenna Minimizing Harmonic Radiation

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Solution Overview

Problem

Magnetic-field coupling between antenna coils and inductor elements in RFID systems leads to unwanted harmonic radiation, which is not effectively minimized in existing technologies.

Innovation Solution

The antenna device incorporates coil conductors with winding axes orthogonal to each other within a multilayer body, reducing magnetic-field coupling and allowing for a miniature antenna with superior radio frequency characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If coil conductors are integrated into the same multilayer body, then device miniaturization is achieved, but magnetic-field coupling occurs causing unwanted harmonic radiation

Engineering Contradiction:
Improveantenna device sizeVSAvoidunwanted harmonic radiation
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies dimensional separation by arranging coil conductors with winding axes in different spatial dimensions (orthogonal directions). First coil conductors wind in one direction while second coil conductors wind in a perpendicular direction, causing their magnetic fields to be oriented orthogonally. This dimensional arrangement minimizes magnetic-field coupling between conductors while maintaining compact integration within the multilayer body, thereby reducing unwanted harmonic radiation despite close proximity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple coil conductors are arranged closely together, then integration density is improved, but magnetic-field coupling increases causing harmonic radiation

Engineering Contradiction:
Improveintegration densityVSAvoidharmonic radiation
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent employs asymmetric arrangement of coil conductors with different winding orientations. Rather than symmetric placement that would maximize coupling, the conductors are arranged with winding axes at orthogonal angles to each other. This asymmetric configuration ensures that magnetic field lines from one conductor are perpendicular to the plane of adjacent conductors, minimizing flux linkage and reducing harmonic radiation while maintaining high integration density.

Inventive Principle:
Principle #4Asymmetry

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

This configuration minimizes unwanted harmonic radiation, enabling the development of a compact antenna device with enhanced radio frequency performance and facilitating the miniaturization of radio communication apparatus.

Implementation Method 1

when transmitting, a transmitting signal exiting the IC chip 1 passes though the EMC filter and the matching capacitor C14 as indicated by rightward arrows before reaching the antenna coil 2, creating a magnetic field in the antenna coil 2 to thereby perform communication

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

When receiving, an induction voltage is created by the magnetic field passing through the antenna coil 2

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2811656B1Antenna device and wireless communication device
Publication Date: 2020.06.10 MURATA MFG CO LTD
  • EP2811656B1 patent drawingFigure 1
  • EP2811656B1 patent drawingFigure 2A~2B
  • EP2811656B1 patent drawingFigure 3

AI summary

In order to minimize radiation of unwanted harmonics, an antenna device (101) includes a multilayer body (10) including magnetic layers or dielectric layers that are stacked, a first coil conductor (21) that has a winding axis in a direction orthogonal to the stacking direction of the multilayer body (10), the first coil conductor (21) being provided in the multilayer body (10), and a second coil conductor (22) that has a winding axis in a direction orthogonal to the winding axis of the first coil conductor (21), the second coil conductor (22) being provided in the multilayer body (10).