RFID Reader Antenna Attenuator for Receiver Saturation
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Solution Overview
Problem
Conventional RFID label printers face challenges in stabilizing the reception of identification information from RFID tags due to increased voltage standing wave ratio (VSWR), leading to receiver saturation, especially when the antenna impedance is not matched with the RFID tag and base paper characteristics.
Innovation Solution
Incorporating attenuating means between the antenna and directional coupler in the RFID reader writer to reduce radio wave power input to the receiver, thereby mitigating saturation caused by increased VSWR, and using a control circuit to manage the print mechanism and RFID communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single antenna is used for both transmission and reception of radio waves, then device complexity is reduced, but receiver saturation occurs due to increased voltage standing wave ratio when antenna impedance is not matched with RFID tag and base paper characteristics
Solution Approach 1:
A variable attenuator is introduced as an intermediary component between the antenna and the receiver. This attenuator dynamically adjusts the radio wave power level to prevent receiver saturation while maintaining stable identification information acquisition, resolving the contradiction between using a single antenna and preventing receiver saturation.
2Adaptability or versatility
If antenna impedance is not matched with RFID tag and base paper characteristics, then adaptability to different configurations is improved, but voltage standing wave ratio increases causing receiver saturation
Solution Approach 1:
The patent employs a variable attenuator that can dynamically adjust its attenuation level based on the actual communication conditions. This dynamic adjustment allows the system to adapt to different impedance configurations without causing receiver saturation, maintaining both versatility and communication stability.
Solution Approach 2:
The system changes the power level parameter of the radio wave by adjusting the variable attenuator's attenuation value. This parameter adjustment compensates for impedance mismatches and prevents receiver saturation, enabling stable communication across different configurations.
3Reliability
If attenuating means is added to reduce radio wave power to prevent receiver saturation, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The variable attenuator provides dynamic control over radio wave power levels, allowing the system to adapt to different communication conditions. This dynamic capability improves communication reliability while the integrated design minimizes the increase in device complexity.
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
Stable acquisition of identification information from RFID tags is ensured without receiver saturation, even with varying antenna impedance and base paper characteristics, by attenuating the radio wave power, thus improving communication reliability.
Implementation Method 1
an antenna commonly used for transmission of a radio wave to a radio frequency identification tag and reception of a radio wave that has been modulated with at least identification information and transmitted from a radio frequency identification tag
Implementation Method 2
a directional coupler which is connected between the transmitter and the receiver, guides the radio wave output from the transmitter to the antenna and guides the radio wave received by the antenna to the receiver
Implementation Method 3
attenuating means, connected between the antenna and the directional coupler, for attenuating the radio wave guided to the receiver to reduce saturation of the receiver due to an increase in voltage standing wave ratio of the antenna
Data Source
AI summary
An identification information reader includes an antenna commonly used for transmission of a radio wave to a radio frequency identification tag and reception of a radio wave that has been modulated with at least identification information and transmitted from a radio frequency identification tag, a transmitter which outputs a radio wave to be transmitted from the antenna, a receiver which demodulates a radio wave received by the antenna to acquire at least the identification information, a directional coupler which is connected between the transmitter and the receiver, guides the radio wave output from the transmitter to the antenna and guides the radio wave received by the antenna to the receiver, and an attenuator which is connected between the antenna and the directional coupler and attenuates the radio wave guided to the receiver to reduce saturation of the receiver due to an increase in voltage standing wave ratio of the antenna.