Multi-Resonance Antenna for Contactless Smart Cards
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Solution Overview
Problem
Current smart card antennas with a single resonant frequency are inadequate for supporting higher data rates required by evolving communication standards, as they compromise communication range and energy efficiency due to reduced energy in lateral frequency lines.
Innovation Solution
An antenna design featuring multiple and adjustable resonance peaks, including a central peak for the carrier frequency and lateral peaks for data transmission frequencies, achieved through the use of parallel and series resonant circuits (L, C) to optimize energy distribution for both communication range and data rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single resonant frequency antenna is used for contactless smart cards, then the communication range is maintained, but the data transmission rate cannot be increased beyond standard limits
Solution Approach 1:
The antenna is divided into multiple independent resonant circuits, each tuned to a specific frequency (carrier frequency and multiple data transmission frequencies). This segmentation allows the antenna to simultaneously support multiple frequency operations, enabling higher data rates while maintaining communication range through the carrier frequency resonance.
Solution Approach 2:
The antenna structure is designed to perform multiple functions simultaneously: maintaining carrier frequency resonance for communication range and providing resonance at multiple data transmission frequencies for high-speed data transfer. This multi-functionality resolves the contradiction by making the antenna adaptable to both range and speed requirements.
2Speed
If the resonant frequency is optimized for high data rates, then data transmission speed improves, but the communication range is reduced
Solution Approach 1:
The antenna circuit is segmented into multiple resonant circuits operating at different frequencies. One circuit maintains resonance at the carrier frequency (13.56 MHz) to ensure communication range, while other circuits resonate at data transmission frequencies (e.g., 12.56 MHz, 14.56 MHz) to enable high-speed data transfer, thus resolving the range-speed trade-off.
Solution Approach 2:
The antenna design changes the impedance characteristics across multiple frequencies by incorporating parallel resonant circuits with different L and C values. This allows the antenna to present optimal impedance at both the carrier frequency for range and at data frequencies for speed, eliminating the need to choose between range and speed optimization.
3Length of stationary object
If the resonant frequency is optimized for communication range, then range is maintained, but the energy available for high-speed data transmission is reduced
Solution Approach 1:
The energy distribution is segmented across multiple resonant circuits. Each circuit is optimized for its specific frequency function, ensuring that energy is efficiently utilized at both the carrier frequency for range maintenance and at data frequencies for high-speed transmission, thereby maximizing overall energy efficiency.
Solution Approach 2:
By adjusting the inductance and capacitance values in each resonant circuit, the impedance at each frequency is optimized independently. This parameter optimization ensures maximum energy transfer efficiency at the carrier frequency for range and at data frequencies for high-speed communication, resolving the energy allocation contradiction.
4Use of energy by moving object
If a flatter impedance template is chosen to increase lateral line energy, then data transmission energy improves, but the central line height is reduced, harming communication range
Solution Approach 1:
Instead of using a single flatter impedance template that compromises the central line, the invention segments the antenna into multiple resonant circuits. Each circuit creates a sharp resonance peak at its specific frequency, allowing high energy at lateral lines for data transmission while maintaining a tall central line for communication range.
Solution Approach 2:
The antenna combines multiple resonant circuits with different impedance characteristics to create a composite structure. This composite design allows the simultaneous presence of sharp resonance peaks at multiple frequencies, achieving both high lateral line energy for data and high central line energy for range, which a single flat template cannot provide.
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 design allows for independent optimization of energy for carrier and data transmission, maintaining communication range while enhancing data transmission quality and rate without sacrificing either performance.
Implementation Method 1
the antenna is configured to present simultaneously at least three resonance peaks, namely a first peak centered on the frequency of the carrier F0, and two lateral peaks centered on the data transmission frequencies F0+f and F0-f
Data Source
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AI summary
Improved antenna for contactless chip card The invention relates to an antenna for contactless chip card making it possible to communicate with a chip card reader with the aid of a carrier signal of frequency F0modulated by a data signal of frequency f, characterized in that it is configured to present at the same time, for a given bitrate of communication between the chip card and the reader, at least three resonance peaks (P1,P2,P3), namely a first peak (P2) close to the frequency of the carrier F0, and at least 2nlateral peaks (P1,P3) close to the data transmission frequencies Fo +. n.f and F0- n.f, where n represents the number of harmonics of the signal to be transmitted.