Antenna Impedance Matching Network With Single-Point Tuning

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Solution Overview

Problem

Existing impedance matching devices for radio frequency antennas suffer from long impedance matching phases, which consume significant energy and are inefficient due to the need for multiple combinations of adjustable components to find minimum reflected power, especially when used in battery-powered systems.

Innovation Solution

A device with a simplified impedance matching network comprising fixed-value and single adjustable-value inductive or capacitive components, using a directional coupler and a diode with an analog-to-digital converter to measure reflected power, allowing for quicker adaptation by varying the adjustable component until a single minimum voltage is reached, reducing the scanning range and duration of the matching phase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple adjustable components are used in the impedance matching network, then the impedance matching can handle a wider range of impedance variations, but the matching phase becomes longer and consumes more energy

Engineering Contradiction:
Improveimpedance matching rangeVSAvoidmatching phase duration
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The impedance matching network is segmented into fixed-value components and a single adjustable-value component. The fixed components handle the majority of impedance matching requirements, while the single adjustable component fine-tunes the matching, thereby reducing the complexity of the scanning process and shortening the matching phase duration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the single adjustable-value component based on real-time impedance conditions. By making the component value variable rather than fixed, the system can adapt to impedance changes without requiring multiple adjustable components, thus maintaining versatility while reducing matching time.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If multiple adjustable components are used in the impedance matching network, then the impedance matching can handle a wider range of impedance variations, but the energy consumption increases

Engineering Contradiction:
Improveimpedance matching rangeVSAvoidenergy consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The impedance matching network is segmented into fixed-value components and a single adjustable-value component. The fixed components handle the majority of impedance matching requirements, while the single adjustable component fine-tunes the matching, thereby reducing the complexity of the scanning process and shortening the matching phase duration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system discards the need for multiple adjustable components and recovers energy by using only a single adjustable component. This reduction in component count directly reduces the energy required for scanning and adjustment, making the system more energy-efficient while maintaining adequate impedance matching capability.

Inventive Principle:
Principle #34Discarding and recovering

3Loss of time

If a single adjustable component is used in the impedance matching network, then the matching phase is shorter and energy consumption is reduced, but the detector sensitivity requirements increase

Engineering Contradiction:
Improvematching phase durationVSAvoiddetector sensitivity
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The system uses a feedback mechanism where the detector monitors the reflected power and provides information to adjust the single adjustable-value component. This feedback loop enables the system to achieve accurate impedance matching with a single component by continuously optimizing based on real-time measurements, thereby reducing matching time without sacrificing precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The fixed-value components are pre-configured to provide initial impedance matching, performing preliminary action before the single adjustable component fine-tunes the matching. This preliminary setup reduces the adjustment range required and minimizes the time and sensitivity needed for the final optimization step.

Inventive Principle:
Principle #10Preliminary action

4Use of energy by moving object

If a single adjustable component is used in the impedance matching network, then the matching phase is shorter and energy consumption is reduced, but the device complexity increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidnetwork structure
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The impedance matching network is segmented into fixed-value components and a single adjustable-value component. The fixed components handle the majority of impedance matching requirements, while the single adjustable component fine-tunes the matching, thereby reducing the complexity of the scanning process and shortening the matching phase duration.

Inventive Principle:
Principle #1Segmentation

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 approach shortens the impedance matching phase, reduces energy consumption, and allows for impedance matching with a less sensitive detector, as it identifies a single minimum reflected power point, facilitating faster adaptation to the source impedance.

Implementation Method 1

a diode connecting the third port of the coupler to a measurement terminal of the device configured to be connected to an analog-to-digital converter

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 2

an impedance matching network comprising fixed-value inductive and/or capacitive components and a single adjustable-value inductive or capacitive component

Methodology Applied
Scientific EffectImpedance transformation: Electrical Impedance Tomography

Implementation Method 3

a directional coupler comprising a first port configured to be connected to a source of a radio frequency signal, a second port to which a signal received by the first port is transmitted and a third port to which a signal received by the second port is transmitted

Methodology Applied
Scientific EffectSignal coupling:

Data Source

PatentEP3913812A1Impedance matching
Publication Date: 2021.11.24 STMICROELECTRONICS (TOURS) SAS
  • EP3913812A1 patent drawingFigure 1~2
  • EP3913812A1 patent drawingFigure 3~4
  • EP3913812A1 patent drawingFigure 5~7

AI summary

This description relates to a device comprising: an antenna (2); a directional coupler (4) comprising a first port (401) receiving a radio frequency signal, a second port (402) to which a signal received by the first port (401) is transmitted and a third port (403) to which a signal received by the second port (402) is transmitted; an impedance matching network (3') connected between the second port (402) and the antenna (2) and comprising inductive and/or capacitive components (C1', L1, C2', L2, C3) of which a single inductive or capacitive component (C3) has an adjustable value; and a diode (6) connecting the third port (403) of the coupler (4) to a measurement terminal (104) of the device (1') configured to be connected to an analog-to-digital converter.