RFID Transponder Frequency Offset for Weak Transformer Coupling
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Solution Overview
Problem
Existing contactless radio-frequency data transmission systems face significant challenges with weak transformer connections, leading to deteriorated transmission characteristics and noise issues, especially in cashless payment solutions where the transformer connection coefficient is low, and existing solutions require changes to the receiver hardware or software, making them impractical for widespread implementation.
Innovation Solution
The method involves transmitting a signal with a frequency different from the receiver's carrier frequency, allowing the receiver to analyze the combined carrier and modulated subcarrier frequencies without physically using the subcarrier signal, which enables effective data transmission even with weak transformer connections without altering the receiver's hardware or software, and uses an electromagnetic wave generator to modulate and demodulate signals efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transformer connection is used between the antenna systems of the receiver and transmitter, then short-distance data transmission is enabled, but transmission characteristics deteriorate when the transformer connection is weak (k=0.2-0.001)
Solution Approach 1:
The patent changes the frequency parameter of the transmitted signal from the standard carrier frequency to a frequency that is offset by the subcarrier frequency. This parameter change allows the signal to be transmitted effectively even through weak transformer connections, as the frequency offset creates a detectable difference that can be recovered at the receiver side without requiring strong coupling between antennas.
Solution Approach 2:
The patent introduces a frequency offset as an intermediary mechanism that mediates between the transmitter and receiver in weak transformer connection conditions. By transmitting at a frequency offset by the subcarrier frequency, the system creates an intermediate signal characteristic that can survive weak coupling and still be detected and decoded at the receiver.
2Reliability
If the transponder is shielded or interfered with, then transmission characteristics deteriorate and noise increases, but increasing radiated power is not permitted
Solution Approach 1:
The patent changes the transmission frequency parameter to be offset from the carrier frequency by the subcarrier frequency. This parameter change makes the transmission more robust against shielding and interference because the frequency offset creates a distinctive signal characteristic that can be differentiated from noise and interference at the receiver, without requiring increased power.
3Reliability
If new readers are designed to improve transmission characteristics, then transmission quality improves, but widespread implementation becomes impractical due to existing massively used readers
Solution Approach 1:
Instead of modifying the receiver (reader) to improve transmission characteristics, the patent inverts the approach by modifying the transmitter (transponder) frequency. The transmitter now transmits at a frequency offset by the subcarrier frequency, while existing receivers continue to operate with their standard carrier frequency reception. This inversion allows compatibility with existing readers while achieving improved transmission characteristics.
Solution Approach 2:
The patent makes the transmitter self-adaptive by automatically transmitting at an offset frequency that creates a detectable signal even in weak transformer connections. The transmitter uses its own subcarrier frequency as the offset amount, making the system self-configuring without requiring external modification or coordination with the receiver side.
4Ease of operation
If the transmitter transmits at the carrier frequency, then standard modulation techniques work, but transmission in weak transformer connections fails
Solution Approach 1:
The patent changes the transmission frequency parameter from the carrier frequency to a frequency offset by the subcarrier frequency. This simple parameter change maintains ease of operation as the modulation process remains similar, but dramatically improves reliability in weak transformer connections by creating a detectable frequency difference that can be recovered at the receiver.
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 improves transmission characteristics and reduces noise, enabling reliable data transmission in weak transformer connections without requiring changes to existing receivers, and is suitable for use in mobile devices and other applications, such as cashless payments and sensor data transmission.
Implementation Method 1
the receiver transmits a carrier signal, while the transmitter sends a signal with a frequency that is different from the carrier frequency
Implementation Method 2
a transformer connection between the antenna systems of the receiver and the transmitter is used
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The method and solution can be mainly used for data transmission in cashless payment applications, especially those realized from the mobile phone while using RFID and/or NFC platform. The signals with different frequency are combined in antenna system (M) of the receiver (1) and transmitter (2) and then the carrier signal is separated from the result of the combined signals and the transmitted data are demodulated. The difference between the frequencies has a value, that corresponds to the size of the subcarrier frequency to which the receiver (1) is preset. During transmission the transformer connection coefficient can have the value k = 0,2 - 0,001, while the antenna (3) of the receiver (2) is tuned narrowly to the transmitter's (2) frequency without considering the subcarrier frequency. The transmitter is preferably located on a memory card or on a card with a format and interface of a memory card, e.g. micro SD.