RFID Antenna Circuit With Intermediate Tap for Compact Power Transmission
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Solution Overview
Problem
RFID/NFC antenna circuits face inefficiencies in magnetic field power transmission and coupling due to mechanical and electric constraints, such as reduced surface areas and the presence of batteries or screens, leading to reduced communication distance and increased signal distortion.
Innovation Solution
An RFID antenna circuit design featuring at least three turns with specific connections and capacitance arrangements to maintain a reasonable quality factor, increase radiated or received power, and reduce mutual inductance, allowing for efficient energy and information transmission without signal quality loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna surface area is reduced to fit constrained environments (cards, stickers, mobile devices), then the device compactness is improved, but the magnetic field power transmission efficiency and coupling are degraded
Solution Approach 1:
The antenna is divided into multiple turns (at least three turns) with an intermediate tap connection. This segmentation allows the antenna to maintain compact size while creating multiple inductive pathways that enhance magnetic field generation and coupling efficiency, resolving the contradiction between reduced surface area and power transmission efficiency.
Solution Approach 2:
The patent introduces a third dimension to the antenna design by adding an intermediate tap connection point along the antenna winding. This additional connection dimension enables complex impedance matching and resonance tuning that compensates for the reduced surface area, maintaining magnetic field power transmission efficiency in compact form factors.
2Power
If the number of antenna turns is increased to improve magnetic field power and coupling, then the power transmission efficiency is improved, but the antenna surface area and device complexity increase
Solution Approach 1:
The antenna winding is segmented into multiple turns with an intermediate tap, allowing the magnetic field power to be enhanced through multiple inductive loops within a compact area. The segmentation creates cumulative magnetic field effects without requiring proportional increases in surface area.
Solution Approach 2:
The patent changes the electrical parameters by introducing the intermediate tap connection, which enables optimized impedance matching and resonance frequency tuning. This parameter change allows the antenna to achieve high magnetic field power with fewer physical turns, reducing the required surface area while maintaining power transmission efficiency.
3Reliability
If the antenna quality factor is increased to improve signal selectivity, then the bandwidth is reduced and signal distortion increases
Solution Approach 1:
The intermediate tap connection enables dynamic impedance matching and resonance tuning. The antenna system can adapt its electrical characteristics to optimize the balance between quality factor and bandwidth, preventing excessive signal distortion while maintaining signal selectivity through adjustable resonant conditions.
Solution Approach 2:
The patent introduces adjustable electrical parameters through the intermediate tap connection, allowing optimization of the resonance frequency and impedance matching. This parameter adjustment capability enables the antenna to maintain appropriate quality factor levels without excessive bandwidth reduction, thereby preventing signal distortion while preserving signal selectivity.
4Adaptability or versatility
If mechanical constraints (battery, screen, conductor support) are added to the device, then the device functionality is improved, but the antenna coupling efficiency and communication distance are reduced
Solution Approach 1:
The segmented antenna structure with intermediate tap creates multiple inductive pathways that can be optimized to operate effectively in the presence of mechanical constraints. The segmentation allows the antenna to maintain coupling efficiency by distributing the magnetic field generation across multiple smaller loops, reducing interference from nearby conductors, batteries, and screens.
Solution Approach 2:
The intermediate tap connection acts as an intermediary element that enables impedance matching and resonance tuning to compensate for the detrimental effects of mechanical constraints. This intermediary connection point allows the antenna system to adapt its electrical characteristics, maintaining coupling efficiency and communication distance despite the presence of interfering components.
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
The design enhances radio efficiency and bandwidth while minimizing mutual inductance, enabling effective communication over increased distances without compromising signal quality, even in constrained environments.
Implementation Method 1
the efficiency of coupling by mutual inductance between the two magnetic antennas
Implementation Method 2
at least one tuning capacitance for tuning at a prescribed tuning frequency
Data Source
AI summary
The invention concerns an RFID/NFC antenna circuit. An antenna (L) is formed by at least three turns (S), the antenna having a first end terminal (D) and a second end terminal (E), two access terminals (1, 2) to connect a charge, a tuning capacitance (C1, ZZ) for tuning at a prescribed tuning frequency, an intermediate tap (A) connected to the antenna (L) and distinct from terminals (D, E), a first connector (CON1A) connecting the intermediate tap (A) to terminal (1), a second connector (CON2E) connecting end terminal (E) to the capacitance terminal (C1E). A third connector (CON31, CON32) connects the capacitance terminal (C1X) and the second access terminal (2) respectively to a first point (P1) of the antenna (L) and to a second point (P2) of the antenna (L) connected to the first point of the antenna (L) at least one turn (S) of the antenna (L).