MiniSD RFID Tag Powered by Host Device Antenna
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Solution Overview
Problem
The miniaturization of passive RFID tags is hindered by the size of loop antennas required for power generation, which prevents their integration into smaller mobile devices without relying on external antennas or oversized form factors.
Innovation Solution
A memory card-compatible RFID tag with an integrated small inductive element that receives power from a host device, allowing it to operate independently of external antennas and maintain functionality through 'hidden' commands within existing memory card access protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a passive RFID tag uses a loop antenna for power generation, then the tag can operate independently, but the antenna size becomes large preventing integration into small mobile devices
Solution Approach 1:
The patent extracts the power generation function from the RFID tag itself by removing the loop antenna from the tag and placing it in the host device. The tag now only contains the RFID circuitry and relies on the host device's antenna for both power generation and communication, enabling miniaturization of the tag to fit in small form factors like microSD cards.
Solution Approach 2:
The host device's antenna serves multiple functions: it acts as both the power generation antenna for the passive RFID tag and the communication antenna for NFC operations. This multi-functionality eliminates the need for a separate antenna in the tag, resolving the size constraint.
2Area of moving object
If the loop antenna size is reduced to fit small devices, then the device form factor improves, but the power supply voltage cannot reach the critical value needed for tag operation
Solution Approach 1:
The patent removes the power generation function from the tag's antenna and transfers it to the host device's antenna. This allows the tag to use a larger host antenna for reliable power generation while keeping the tag itself small, eliminating the voltage threshold problem associated with miniaturized antennas.
3Reliability
If external antennas are used for RFID functionality, then power generation is reliable, but the device requires oversized form factor or external components
Solution Approach 1:
The patent merges the RFID tag and host device into an integrated system where the host device's antenna serves dual purposes: generating power for the passive tag and enabling NFC communication. This integration eliminates the need for separate external antennas while maintaining reliable power generation and communication functions.
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 the implementation of RFID functionality in small form factors, such as miniSD cards, without the need for external antennas, ensuring compatibility with standard memory card slots and maintaining power efficiency by using host device power management.
Implementation Method 1
small inductive device powered by a host device
Implementation Method 2
transmit information by broadcasting on an RF carrier frequency
Data Source
AI summary
A memory card compatible RFID card includes a smartcard controller that receives power from a host device. The RFID card also includes a small inductive device capable of inductive coupling with an RFID reader. The small inductive device is small enough to fit in the form factor of a memory card. Commands may be sent to the RFID card to keep the RFID card powered.