Coaxial RFID Power Adapter for Cable Loss Measurement

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Solution Overview

Problem

RFID systems face challenges in accurately measuring signal power and transmission losses in coaxial connections, which limits the reading range and efficiency, especially in logistics and distribution centers, due to unknown properties of coaxial cables and the need for specialized antennas and devices.

Innovation Solution

An adapter device is inserted into the coaxial connection between the RFID reading device and the antenna, equipped with measuring units to determine forward and return signal power, allowing for the calculation of transmission losses and attenuation, and can be used with any RFID reading device and antenna, providing a cost-effective solution for optimizing reading range and detecting faulty components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transmission power is set to maximum permitted value due to unknown cable properties, then safety is ensured, but reading range is reduced due to unutilized transmission power

Engineering Contradiction:
ImprovesafetyVSAvoidreading range
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The adapter device performs preliminary measurement of cable attenuation and VSWR values during installation or maintenance. These measured values are stored and later used to calculate the actual transmission power, allowing the system to operate at optimal power levels rather than always using maximum permitted power.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors cable properties through the adapter device and uses this feedback information to dynamically adjust transmission power settings. The measured attenuation and VSWR values provide feedback that enables optimization of transmission power to maximize reading range while maintaining safety.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If cable attenuation is assumed to be zero for safety, then transmission power is not fully utilized, but measurement precision is improved by having known reference values

Engineering Contradiction:
Improvecable property measurementVSAvoidtransmission power utilization
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The adapter device automatically measures and stores cable attenuation and VSWR values without requiring manual intervention or specialized equipment. The system serves itself by performing these measurements during normal operation or installation, eliminating the need for separate calibration procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces traditional manual cable testing methods with automated electronic measurement through the adapter device. The measuring unit electronically determines cable properties without requiring physical cable disconnects or specialized test equipment, streamlining the process.

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

3Measurement precision

If specialized antennas with integrated measuring functionality are used, then measurement capability is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvesignal power measurementVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measuring functionality is segmented into a separate, standalone adapter device that can be attached to any existing antenna. This separates the measurement function from the antenna itself, allowing each component to remain simple while the system as a whole gains measurement capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adapter device acts as an intermediary between the RFID reading device and the antenna. It interfaces with the existing antenna without requiring modifications to either the reader or antenna, providing measurement functionality through this intermediate component.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of time

If coaxial cables are pre-terminated at factory, then installation time is reduced, but reliability deteriorates due to mechanical damage during installation or aging

Engineering Contradiction:
Improveinstallation timeVSAvoidcable connection reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The adapter device performs preliminary measurement of cable properties during installation or maintenance, creating a baseline record of the cable's condition. This early measurement allows for detection of degradation over time and proactive maintenance before failures occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system provides continuous feedback on cable health through repeated measurements of attenuation and VSWR. This feedback mechanism enables monitoring of cable degradation due to aging or mechanical stress, allowing for timely maintenance decisions.

Inventive Principle:
Principle #23Feedback

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 adapter device enables precise measurement of signal power and transmission losses, allowing for appropriate power adjustment and early detection of cable deterioration, thereby optimizing the reading range and maintaining maximum permissible signal levels, and can be used across various systems for cost-effective evaluation and predictive maintenance.

Implementation Method 1

RFID transponders can, in principle, be active, meaning they have their own power supply and generate electromagnetic radiation independently

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

if the transmission losses or cable attenuation values ​​are unknown

Methodology Applied
Scientific EffectSignal attenuation: Absorption (EM radiation)

Implementation Method 3

passive transponders drawing the necessary energy from the transmission energy of the reading system

Methodology Applied
Scientific EffectElectromagnetic energy transfer: Electromagnetic Induction

Data Source

PatentEP4411393B1Adapter device and method for measuring signal power in a coaxial connection
Publication Date: 2024.12.25 SICK AG
  • EP4411393B1 patent drawingFigure 1~2
  • EP4411393B1 patent drawingFigure 3~4
  • EP4411393B1 patent drawingFigure 5~6

AI summary

An adapter device (12) for measuring the signal power in a coaxial connection (14) from an RFID reading device (10) to a second device (16) is described. The adapter device (12) has a first coaxial connector (38) and a second coaxial connector (40) for inserting the adapter device (12) into the coaxial connection (14), as well as a measuring unit (42) configured to determine the signal power of a signal propagating from the first coaxial connector (38) to the second coaxial connector (40) and/or vice versa. The first coaxial connector (38) and the second coaxial connector (40) are detachable, so that the adapter device (12) can be selectively inserted into or removed from the coaxial connection (14).