RFID Leakage Signal Removal via Phase Shifting

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

RFID systems face inefficiencies due to transmission leakage signals, which degrade identification perception and increase costs with multiple antennas and circulators, and existing signal separation devices like circulators or directional couplers are not ideal, causing signal leakage.

Innovation Solution

An apparatus and method that utilize a signal separation unit, a removing unit, and a phase shifter to generate and control signals that cancel out transmission leakage signals, comprising components like resistors, inductors, capacitors, and time delay elements, and a control unit to adjust signal size and phase, effectively removing leakage across all frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple antennas are used to separate transmission and reception signals, then separation between transmission and reception signals is improved, but device complexity and manufacturing costs increase

Engineering Contradiction:

Improveseparation between transmission and reception signalsVSAvoidnumber of antennas

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple antenna functions into a single antenna by using a circulator to separate transmission and reception signals through different ports of the same antenna, eliminating the need for multiple physical antennas while maintaining signal separation

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The circulator acts as an intermediary device that redirects transmission signals to the antenna and reception signals from the antenna to the receiver, enabling signal separation without requiring multiple antennas

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a circulator or directional coupler is used with one antenna for both transmitting and receiving signals, then device complexity is reduced, but transmission signal leakage into the receiving path occurs

Engineering Contradiction:

Improvenumber of antennasVSAvoidtransmission signal leakage

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the leakage signal from the receiving path using a directional coupler, separates it using a circulator, and removes it through a removing unit, eliminating the harmful leakage while maintaining the simplicity of using one antenna for both transmission and reception

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful leakage signal into a removable component by using the directional coupler to tap it off and the removing unit to eliminate it, transforming the problem of leakage into an opportunity for active signal management and purification

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If a circulator or directional coupler is used to separate transmission and reception signals, then manufacturing costs are reduced, but transmission signal leakage occurs deteriorating identification perception

Engineering Contradiction:

Improvemanufacturing costsVSAvoididentification perception

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the removing unit continuously monitors and removes leakage signals from the receiving path, ensuring high identification precision while maintaining cost-effective single-antenna design with circulator

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

This solution improves reception sensitivity and tag identification capabilities, increasing identification speed and distance while reducing signal loss and simplifying the RFID system's circuitry, and is adaptable to various frequency bands and environmental changes.

Implementation Method 1

a phase shifter which generates a phase control leakage signal having a phase different from a phase of the removing signal by adjusting at least one of a phase of the first transmission leakage signal and a phase of the second transmission leakage signal

Methodology Applied

Scientific EffectPhase shift:

Implementation Method 2

a removing unit which generates a removing signal having a given value in reference to at least one of a value of the first transmission leakage signal and a value of the second transmission leakage signal by using the transmission signal

Methodology Applied

Scientific EffectSignal cancellation:

Data Source

PatentUS8463201B2Apparatus and method for removing transmission leakage signal

Publication Date: 2013.06.11 HANWHA VISION CO LTD

AI summary

An apparatus and method for removing a transmission leakage signal from a radio frequency identification (RFID) reader are provided. The apparatus includes a removing unit having a device of a large impedance and a phase shifter capable of a wide range phase change with respect to a leakage signal, thereby optimally removing the transmission leakage signal irrespective of a change in the frequency characteristics and a change in the length of a cable.