Wireless IC Inductance Element Impedance Matching
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Solution Overview
Problem
The existing wireless IC devices in RFID systems face challenges in impedance matching between the wireless IC chip and radiation plates, leading to inefficient energy transmission due to high impedance of inductance elements at connection points.
Innovation Solution
The implementation of a wireless IC device with a feeder circuit and radiation plate coupled through an inductance element featuring stacked layers of electrically connected coil conductors, where a coil conductor is positioned at the end of the coil axis to face the radiation plate near the virtual ground, minimizing impedance and maximizing magnetic field presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coil conductors are arranged in the vicinity of connection points to the wireless IC chip, then the inductance elements can be electrically connected to the wireless IC chip, but the impedance of the inductance elements increases making it difficult to ensure impedance matching between the wireless IC chip and the radiation plates
Solution Approach 1:
Instead of connecting the radiation plate to the end of the coil conductor (high impedance point), the invention connects the radiation plate to the middle portion of the coil conductor (low impedance point near virtual ground). This inversion of the connection position resolves the impedance matching problem by utilizing the natural impedance distribution along the coil conductor.
Solution Approach 2:
The invention utilizes different impedance characteristics at different locations of the coil conductor. The middle portion of the coil conductor has lower impedance and is suitable for connecting to the radiation plate, while the end portion has higher impedance and is suitable for connecting to the wireless IC chip. This local differentiation of connection points optimizes impedance matching.
2Productivity
If coil conductors are arranged near the wireless IC chip connection points, then electrical connection is achieved, but energy transmission efficiency between the feeder circuit and the radiation plate deteriorates
Solution Approach 1:
The invention inverts the conventional connection approach by connecting the radiation plate to the middle portion of the coil conductor rather than the end. This inversion places the radiation plate at a location with lower impedance and higher current density, maximizing energy transfer efficiency and reducing energy losses in the transmission path.
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 arrangement ensures desirable impedance matching between the wireless IC and radiation plate, enhancing the efficiency of energy transmission between the feeder circuit and radiation plate.
Implementation Method 1
a coil conductor electrically connected in a middle portion of the inductance element is arranged at an end position in a coil axis direction and faces the radiation plate
Data Source
AI summary
A wireless IC device includes a wireless IC chip, a feeder circuit substrate which is coupled to the wireless IC chip and includes a feeder circuit including an inductance element, and a radiation plate. The inductance element includes a plurality of stacked layers having coil conductors electrically connected, and a coil conductor electrically connected in a middle portion of the inductance element is arranged at an end position in the coil axis direction and faces a coupling portion of the radiation plate.