Contactless Communication Circuit with Phase-Synchronized Sideband Transmission
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Solution Overview
Problem
Current ISO/IEC 14443 and NFC technologies face challenges in achieving effective coupling between a reader and small contactless objects like micro SD cards due to their small antenna size and the metallic environment of host devices, requiring complex setups with multiple antennas and electronic components.
Innovation Solution
The solution involves generating one of the sidebands independently of the reader, using a circuit that modulates a carrier signal derived from the received electromagnetic field, amplifies the response signal, and transmits it through a separate transmission antenna, with separate tuning frequencies for receiver and transmitter resonant circuits to minimize mutual inductance and eliminate reciprocal disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retro modulation of reader's electromagnetic field is used for contactless communication, then data transmission can be achieved, but the coupling between reader and small contactless objects is insufficient due to small antenna size and metallic environment
Solution Approach 1:
The patent divides the communication system into two independent parts: the reader that generates the electromagnetic field, and the contactless object that generates its own field. This segmentation allows each component to be optimized independently, improving coupling reliability without requiring complex integrated solutions.
Solution Approach 2:
The patent combines the transmitter and receiver functions into a single antenna system at the contactless object. The same antenna both receives the reader's field and transmits the object's own field, simplifying the device structure while maintaining reliable communication through the object's independent field generation.
2Reliability
If minimum field amplitude modulation is used to comply with reader sensitivity, then data transmission meets standard requirements, but very small contactless objects with small antenna surface area cannot achieve sufficient coupling
Solution Approach 1:
The contactless object generates its own electromagnetic field independently, without relying on the reader's field amplitude. This self-service approach allows very small objects with minimal antenna area to achieve reliable communication by transmitting their own field rather than modulating an external field.
3Ease of operation
If embedded operation in host device is implemented, then portability is improved, but metallic environment of host device further reduces coupling between contactless object and reader
Solution Approach 1:
The contactless object proactively generates its own electromagnetic field to counteract the detrimental effects of the metallic environment. By creating an independent field rather than relying on external modulation, the system pre-compensates for signal loss and coupling reduction caused by metallic shielding in portable devices.
4Reliability
If separate transmission and reception antennas are used, then mutual inductance is minimized and reciprocal disturbances are reduced, but device complexity increases
Solution Approach 1:
The patent merges the transmission and reception functions into a single antenna at the contactless object. This unified approach eliminates mutual inductance issues between separate antennas while maintaining signal quality, as the object's transmitted field is generated independently rather than received and re-transmitted.
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 approach enables efficient communication between a reader and small contactless objects by enhancing coupling, simplifying the implementation, and reducing the need for additional electronic components, while maintaining effective data detection and transmission.
Implementation Method 1
a certain amount of electromagnetic field provided by a reader must be modulated by the proximity contactless chip object
Implementation Method 2
The transmission signal is derived from the reception frequency received by the reception antenna
Data Source
Figure 1~3B
Figure 4~8
Figure 9~12
AI summary
The present invention relates to an activated contactless communication circuit (1), including: a means for receiving and transmitting a data-carrying electromagnetic field (5, 6, 7, 8); a first circuit resonating with a first antenna (7, 13) for receiving data; and a second circuit resonating with a second antenna (8, 43) for transmitting data, said first and second resonating circuits being separate from each other. The circuit is characterized in that said transmission is carried out at a frequency phase-synchronized with the frequency of the electromagnetic field for reception. The invention also relates to the corresponding method.