Buried RFIC Wireless IC Device Antenna Interference Reduction
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Solution Overview
Problem
RFID tags for the HF band face interference issues due to the mounting of RFIC elements intersecting with the antenna coil, leading to increased occupation area and reliability concerns, especially with open faults in lamination type constructions.
Innovation Solution
A wireless IC device design where the RFIC element is buried within an element body with the antenna coil, using metal pins and wiring patterns to connect the RFIC element's terminals to the antenna coil, reducing magnetic field interference and improving electric characteristics by spacing the RFIC element away from the antenna coil and eliminating the need for complex multilayer substrate routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the mounting surface for mounting the RFIC element intersects with the winding axis of the antenna coil, then the occupation area is reduced, but the RFIC element interferes with the magnetic field formation of the antenna coil
Solution Approach 1:
The patent transitions from planar mounting to three-dimensional embedding. The RFIC element is embedded within the element body at a position that does not intersect with the winding axis of the antenna coil, utilizing the thickness dimension to resolve the conflict between compact area and magnetic field interference.
Solution Approach 2:
The RFIC element is nested within the element body, which is itself part of the overall antenna assembly. This nested structure allows the RFIC element to be positioned inside the element body volume without occupying space that would interfere with the antenna coil's magnetic field formation.
2Area of stationary object
If a lamination type antenna coil is built into a multilayer substrate with via-hole type interlayer connection conductors, then the occupation area is reduced, but open faults easily occur due to lamination deviation
Solution Approach 1:
The patent extracts the antenna coil from the multilayer substrate structure and implements it as a planar wiring pattern on the element body. This eliminates the via-hole type interlayer connection conductors and their associated lamination deviation problems, while maintaining compact form factor through the element body integration.
Solution Approach 2:
The patent segments the antenna coil into multiple wiring patterns (first wiring pattern, second wiring pattern, third wiring pattern) that are distributed across different surfaces of the element body. This segmentation approach maintains the functional equivalence of the lamination structure while avoiding the reliability issues of interlayer connections.
3Device complexity
If base material layers are increased in thickness to reduce the number of interlayer connection conductors, then the manufacturing complexity is reduced, but the interlayer connection conductors are increased in diameter
Solution Approach 1:
The patent removes the interlayer connection conductors entirely by extracting the antenna coil from the multilayer substrate architecture. The antenna function is achieved through planar wiring patterns on the element body surfaces, eliminating the need for thick interlayer connection conductors and their associated manufacturing constraints.
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 solution effectively reduces interference with the magnetic field of the antenna coil, enhances electric characteristics, and miniaturizes the device while maintaining robustness and reliability, allowing for efficient communication and resistance to high-temperature resin molding processes.
Implementation Method 1
an antenna coil disposed in the element body and having one end connected to the first input/output terminal and the other end connected to the second input/output terminal
Implementation Method 2
a first metal pin including a first end and a second end reaching the first principal surface and the second principal surface of the element body and connected at the first end to the first wiring pattern
Data Source
AI summary
A wireless IC device includes an element body including first and second principal surfaces, an RFIC element buried in the element body, and an antenna coil disposed in the element body. The antenna coil includes a first wiring pattern provided on the second principal surface, a first metal pin reaching the first principal surface and the second principal surface, a second metal pin reaching the first principal surface and the second principal surface, and a second wiring pattern provided on the first principal surface. Terminal surfaces of the first input/output terminal and the second input/output terminal of the RFIC element face the second principal surface of the element body and are spaced away from the antenna coil while being connected to the first wiring pattern through first and second conductors extending from the second principal surface of the element body in a direction of the first primary surface.