RFID Tag Energy Storage for Multi-Protocol Backscattering
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Solution Overview
Problem
In dense reader environments, RFID systems face challenges in filtering out unwanted adjacent reader transmissions, making it difficult to effectively backscatter RF signals due to asymmetric communication links and varying time durations across different RFID protocols.
Innovation Solution
RFID tags equipped with an antenna and a storage module that store energy from received RF signals, allowing them to maintain voltage and backscatter signals independently of an internal power supply, supporting multiple protocols with different time durations by selectively switching capacitors to manage voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If passive transponders are used in dense reader environments, then the system can operate without internal power supplies, but the receive signal power becomes extremely weak (1 nanowatt or less) making it difficult to filter out unwanted adjacent reader transmissions
Solution Approach 1:
The patent applies preliminary action by storing energy from received RF signals in a storage module (capacitor) before the tag needs to operate independently. This pre-stored energy enables the tag to maintain voltage during time durations without received power, allowing reliable operation and backscattering even in dense reader environments where signal filtering is difficult.
2Power
If RFID readers transmit at high power (1 watt), then they can effectively communicate with transponders, but unwanted adjacent reader transmissions become difficult to filter out
Solution Approach 1:
The patent converts the harmful effect of high-power adjacent reader transmissions into a beneficial resource. The storage module captures and stores energy from these ambient RF signals (including unwanted transmissions), transforming them into useful stored energy that powers the tag during time durations without direct reader illumination, thereby reducing the tag's dependency on continuous high-power transmissions.
3Duration of action of stationary object
If the storage module stores energy from received RF signals, then the tag can maintain voltage during time durations without received power, but the tag must support multiple protocols with different time durations
Solution Approach 1:
The patent applies dynamics by making the storage module's capacitance adjustable rather than fixed. The system can dynamically change the storage module's capacitance value to match the specific time duration requirements of different RFID protocols (e.g., 125 kHz vs. 13.56 MHz protocols), enabling the same hardware to adaptively support multiple protocols with varying power consumption patterns and time duration requirements.
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
Enables efficient backscattering of RF signals across various protocols, maintaining operational voltage during periods without received power, thereby improving signal transmission and reducing interference from nearby readers.
Implementation Method 1
The antenna is configured to receive an RF signal from any of a plurality of readers
Implementation Method 2
The storage module is coupled to the antenna and configured to store energy associated with the RF signal
Implementation Method 3
the transponder uses radar cross section (RCS) modulation to backscatter information to the readers
Data Source
AI summary
The present disclosure is directed to a system and method for backscattering different radio frequency protocols. In some implementations, a radio Frequency (RF) tag includes an antenna and a storage module. The antenna is configured to receive an RF signal from any of a plurality of readers. Each reader is associated with a different protocol having different time durations. The storage module is coupled to the antenna and configured to store energy associated with the RF signal. In addition, the storage module substantially maintains a voltage in the tag during any of the different time durations independent of an internal power supply.