RFID Tag Energy Storage for Power Margin Management
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Solution Overview
Problem
Passive RFID tags experience operational issues due to insufficient RF power from readers, leading to intermittent functionality caused by negative power margin conditions such as shadowing, impedance mismatch, and RF field interference.
Innovation Solution
Incorporating an energy storage device and power manager in RFID tags to store excess RF power during positive margin conditions and access stored energy during negative margin conditions, allowing continuous operation even when insufficient RF power is received from the reader.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive RFID tags rely solely on received RF power from readers, then device complexity is minimized, but reliability deteriorates due to intermittent functionality under negative power margin conditions
Solution Approach 1:
The patent applies preliminary action by storing excess RF energy in an energy storage device during positive power margin conditions before power deficits occur. This allows the tag to have power readily available during negative power margin conditions, ensuring continuous operation without waiting for favorable RF conditions to recur.
Solution Approach 2:
The patent introduces an energy storage device as an intermediary between the RF receiver and the RFID tag circuitry. This intermediary component buffers energy fluctuations, decoupling the tag's operational reliability from the instantaneous RF power availability, thereby resolving the contradiction between reliability and device complexity.
2Productivity
If RFID tags operate continuously without energy storage, then device complexity remains low, but loss of time increases due to intermittent operation during power fluctuations
Solution Approach 1:
The patent implements continuity of useful action by using the energy storage device to maintain uninterrupted power supply to the RFID tag. During positive power margin conditions, excess energy is stored; during negative power margin conditions, stored energy is discharged. This ensures continuous tag operation and eliminates interruptions caused by RF power fluctuations.
3Reliability
If RFID tags store excess RF energy during positive margin conditions, then reliability improves during negative margin conditions, but device complexity and energy storage requirements increase
Solution Approach 1:
The patent applies parameter changes by monitoring the power margin condition and dynamically adjusting the energy storage device's charging/discharging state. During positive power margin conditions, the energy storage device charges; during negative power margin conditions, it discharges. This dynamic parameter adjustment optimizes reliability while managing the complexity of the energy storage system.
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 ensures continuous RFID tag operation by utilizing stored energy during power fluctuations, enhancing readability and reliability in applications requiring constant tag functionality.
Implementation Method 1
an antenna configured to receive RF power from received wireless RF signals
Implementation Method 2
store excess energy derived from excess received RF power in an energy storage device
Data Source
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AI summary
Excess radio-frequency (RF) power storage in RF identification (RFID) tags, and related systems and methods are disclosed. The RFID tag is configured to operate with RF power received in wireless RF signals (22) from a RFID tag antenna (26) if received RF power meets or exceeds an operational threshold power for the RFID tag. The RFID tag is also configured to store excess energy derived from excess received RF power in an energy storage device (36) if the received RF power exceeds the operational threshold power for the RFID tag. Thus, when RF power received by the RFID tag is not sufficient for operation, the RFID tag can operate from power provided by previously stored excess energy in the energy storage device.