Loop Antenna Design for Magnetic Field Area Expansion

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Solution Overview

Problem

The steep distance attenuation characteristic of magnetic fields, which is more pronounced than that of radio waves, poses a challenge in increasing the area of a radio system using magnetic fields, requiring increased current supply to achieve larger coverage.

Innovation Solution

A loop antenna design featuring a main open loop connected to a signal source and an amplification closed loop of the same shape, arranged on the same or different surfaces of insulating substrates, which enhances the magnetic field generation by accumulating current in the amplification loop, thereby increasing the area of the radio system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If current supplied from transmitter is increased to increase radio area, then coverage area is improved, but energy consumption and system complexity increase

Engineering Contradiction:
Improveradio areaVSAvoidcurrent supply
Core Design Contradiction:
Area of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent introduces a resonant circuit as an intermediary component between the transmitter and the receiving area. This resonant circuit amplifies the magnetic field through resonance effects, allowing the same transmitter current to produce a larger effective radio area without proportionally increasing energy consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operating parameters by tuning the resonant frequency of the circuit components (inductors and capacitors) to match the transmitter frequency. This parameter adjustment creates resonant conditions that amplify the magnetic field strength and extend the radio area without requiring proportional increases in transmitter current.

Inventive Principle:
Principle #35Parameter changes

2Force

If current supplied from transmitter is increased to overcome steep distance attenuation, then magnetic field strength is improved, but energy consumption increases

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidcurrent supply
Core Design Contradiction:
ForceVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic oscillating currents at resonant frequencies to generate the magnetic field. The resonant circuit stores and releases energy periodically, creating sustained oscillations that maintain strong magnetic field strength over distance without requiring continuously high current supply from the transmitter.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

By adjusting the resonant frequency and Q-factor of the circuit components, the patent optimizes the magnetic field strength at the desired operating frequency. This allows the system to achieve strong magnetic fields at specific frequencies without proportionally increasing the overall energy consumption.

Inventive Principle:
Principle #35Parameter changes

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 design allows for a significantly larger magnetic field generation and reception current, effectively expanding the area of the radio system without increasing the current supply from the transmitter, thus overcoming the limitations of steep distance attenuation.

Implementation Method 1

an amplification loop which is a closed loop having a same shape as the main loop, and the main loop and the amplification loop are arranged on a same surface of a flat substrate formed of an insulator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3273539B1Loop antenna
Publication Date: 2020.10.14 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP3273539B1 patent drawingFigure 1~2
  • EP3273539B1 patent drawingFigure 3(a)~3(b)
  • EP3273539B1 patent drawingFigure 4(a)~4(b)

AI summary

Provided is a loop antenna which can contribute to an increase of an area of a radio system using a magnetic field. The loop antenna includes a main loop 1 which is an open loop connected to a signal source 5 or a reception circuit; and an amplification loop 2 which is a closed loop having the same shape as the main loop 1. The main loop 1 and the amplification loop 2 are arranged on a same surface of a flat substrate formed of an insulator. A first capacitance is connected to the main loop 1, and a second capacitance is connected to the amplification loop.