Wireless IC Device Radiation Plate Eddy Current Coupling
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Solution Overview
Problem
Existing RFID wireless IC devices face challenges with low coupling efficiency between primary and secondary coil antennas, leading to large antenna sizes and frequency-dependent coupling, which complicates size reduction and efficient energy transmission.
Innovation Solution
The implementation of a wireless IC device with a power feeding circuit and radiation plate utilizing spiral-shaped inductance elements with opposite winding directions and plate-shaped or spiral-shaped coupling units positioned nearly perpendicular to the inductance elements, inducing eddy currents for high coupling efficiency independent of communication frequency, allowing for a significantly smaller radiation plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inductance value of the secondary coil antenna is increased to improve magnetic field coupling, then the degree of coupling is improved, but the size of the secondary coil antenna becomes large
Solution Approach 1:
The patent changes the coupling mechanism from magnetic field coupling to electric field coupling by introducing a radiation plate. This parameter change allows for smaller antenna dimensions while maintaining or improving coupling efficiency, as the radiation plate creates a capacitive coupling effect that is less dependent on inductance value and more controllable through geometric configuration.
Solution Approach 2:
The radiation plate serves as an intermediary element between the primary and secondary coil antennas. It mediates the coupling by creating an electric field that bridges the two coils, enabling efficient energy transfer without requiring large inductance values or large physical dimensions for the secondary antenna.
2Ease of operation
If both antennas are electric-field-coupled to each other, then coupling is established, but the degree of coupling remains small
Solution Approach 1:
The patent employs a composite structure combining conductive coil antennas with a radiative plate element. This composite configuration integrates both magnetic coupling characteristics of the coils and electric field coupling capabilities of the plate, achieving enhanced overall coupling efficiency that overcomes the limitations of using either mechanism alone.
3Volume of moving object
If the size of the radiation plate is decreased to reduce device size, then compactness is improved, but coupling efficiency may be compromised
Solution Approach 1:
The patent optimizes the radiation plate design by concentrating coupling functionality in specific local regions rather than requiring uniform large-area plates. By positioning the secondary coil antenna at optimal locations relative to the plate and using spiral-shaped inductance elements with specific orientations, efficient coupling is achieved with significantly reduced plate dimensions.
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 configuration achieves a high degree of coupling between the power feeding circuit and radiation plate, enabling efficient energy transmission and reducing the size of the radiation plate, while maintaining stable frequency characteristics and coupling efficiency across various frequencies.
Implementation Method 1
the plate-shaped coupling units are disposed in a vicinity of the at least two inductance elements so as to be nearly perpendicular to the winding axes of the inductance elements, respectively. eddy currents occur in the two plate-shaped coupling units so as to couple the power feeding circuit and the radiation plate with each other
Implementation Method 2
the at least two inductance elements have spiral shapes wound in directions opposite to each other and winding axes of the individual inductance elements are disposed at different positions
Data Source
AI summary
A wireless IC device includes a wireless IC chip, a power feeding circuit substrate including a power feeding circuit including inductance elements, and radiation plates including plate-shaped coupling units. The inductance elements have spiral shapes and are wound in directions opposite to each other. The plate-shaped coupling units in the radiation plates are disposed in a vicinity of the inductance elements so as to be perpendicular or substantially perpendicular to the winding axes of the inductance elements, and eddy currents occur in the plate-shaped coupling units so as to couple the power feeding circuit and the radiation plates with each other. The plate-shaped coupling units may also have spiral shapes.