Resonant Loop Antenna Capacitance Tuning for Wider Wireless Coverage

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Solution Overview

Problem

Existing loop antenna systems face challenges in expanding wireless coverage due to the sharp distance decay of magnetic fields, requiring high current and increased power consumption, and struggle to achieve optimal magnetic field amplification with non-matching capacitor values.

Innovation Solution

The implementation of a loop antenna configuration with a main open loop and an amplification closed loop, both having equal self-inductance, along with resistors and capacitors, allows for maximizing current flow and magnetic field expansion even when capacitor values do not match optimal values, using optimal curved and straight lines to determine capacitance settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a large current is applied to the antenna to expand wireless coverage, then the coverage area is improved, but power consumption increases significantly

Engineering Contradiction:
Improvewireless coverage areaVSAvoidpower consumption
Core Design Contradiction:
Area of stationary objectVSUse of energy by stationary object

Solution Approach 1:

The patent applies magnetic field resonance to amplify the magnetic field without increasing current. By tuning the resonant frequency of the loop antenna system, the magnetic field is naturally amplified through resonant oscillation, achieving expanded wireless coverage while maintaining low power consumption. The resonance effect creates a feedback mechanism where the magnetic field reinforces itself, eliminating the need for high current input.

Inventive Principle:
Principle #18Mechanical vibration

2Strength

If variable capacitors are used to optimize capacitance values for magnetic field amplification, then the magnetic field strength is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidcapacitor adjustment mechanism
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent determines optimal capacitance values through theoretical calculation and design optimization rather than requiring variable capacitors for adjustment. By establishing the relationship between capacitance values and magnetic field strength through mathematical modeling, the invention identifies fixed capacitance values that maximize resonance effect. This eliminates the need for variable capacitors and complex adjustment mechanisms while achieving optimal magnetic field amplification.

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 configuration enables the generation of a relatively large magnetic field with reduced power consumption and cost, allowing for effective wireless coverage expansion even with fixed capacitors, by optimizing current flow through resistor and capacitor combinations.

Implementation Method 1

A current applied to the antenna develops spherical magnetic field distribution on a surface of the antenna

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnetic Induction

Implementation Method 2

A method of amplifying the magnetic field by using a magnetic field resonance effect without increasing a consumption current

Methodology Applied
Scientific EffectMagnetic field resonance: Resonance

Data Source

PatentEP3644439B1Loop antenna and design method for loop antenna
Publication Date: 2023.09.20 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP3644439B1 patent drawingFigure 1~2
  • EP3644439B1 patent drawingFigure 3~4
  • EP3644439B1 patent drawingFigure 5~6

AI summary

Even when at least one of a capacitor (C1) connected to a main loop (1) and a capacitor (C2) connected to an amplification loop (2) cannot be set to an optimal value, a current value of a current (I2) flowing on the amplification loop can be made sufficiently large by setting the capacitors (C1, C2) based on any of an optimal C2 curved line, an optimal C1 curved line, and an optimal C1 straight line that pass through an optimal point (C1opt, C2opt) of the capacitors (C1, C2) and extend along a ridge of contour lines each joining the points where the magnitude of the current (I2) is equal on a diagram showing a relation of values of the capacitors (C1, C2) with the magnitude of the current (I2).