Ground Electrode Antenna with Slits for RFID Resonance
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Solution Overview
Problem
RFID tags require a dedicated antenna, increasing cost and size, and necessitate changes in antenna shape or size when the IC chip is changed, which complicates resonant frequency adjustment.
Innovation Solution
A wireless IC device uses an existing electrode on a circuit board as an antenna, with slits or cutouts to adjust the resonant frequency, eliminating the need for a separate antenna and allowing impedance matching, thereby improving signal transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated antenna is provided in the RFID tag, then the antenna gain is improved, but the device size and manufacturing cost increase
Solution Approach 1:
The patent merges the antenna function with the existing ground electrode on the circuit board. The ground electrode, which is already present for electrical grounding, is configured to also serve as the radiator plate (antenna) for RFID communication. This eliminates the need for a separate dedicated antenna structure, thereby reducing device size while maintaining antenna gain through proper impedance matching and resonant frequency adjustment.
Solution Approach 2:
The ground electrode is given dual functionality: it serves both as an electrical ground reference and as the antenna radiator plate for RFID signals. This multi-functional design allows the same structural element to fulfill multiple roles, avoiding the addition of extra components and reducing overall device complexity and size.
2Reliability
If a dedicated antenna is provided in the RFID tag, then the antenna gain is improved, but the manufacturing cost increases due to additional fabrication processes
Solution Approach 1:
The antenna function is combined with the existing ground electrode that is already part of the circuit board structure. This eliminates the need for separate antenna fabrication processes such as etching, lamination, or assembly of dedicated antenna elements, thereby reducing manufacturing complexity and cost while maintaining effective antenna performance.
Solution Approach 2:
The existing ground electrode structure serves itself by also functioning as the antenna radiator plate. This self-service approach means the antenna capability is inherent in the existing circuit board design, eliminating the need for additional manufacturing steps specifically for antenna production.
3Adaptability or versatility
If the IC chip is changed in the RFID tag, then the functionality is improved, but the antenna design must be changed as well, increasing device complexity
Solution Approach 1:
The ground electrode-based antenna design provides a universal interface that can work with different IC chip types. Since the antenna is integrated into the circuit board's ground structure rather than being a separate component, it maintains consistent electrical characteristics regardless of which IC chip is mounted, allowing IC chip changes without requiring antenna redesign.
Solution Approach 2:
The RFID tag is segmented into functionally independent modules: the IC chip mounted on the circuit board and the ground electrode-based antenna. This segmentation allows the IC chip to be changed or upgraded independently without affecting the antenna design, as the antenna function is decoupled from the specific IC chip implementation.
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 approach achieves miniaturization of the RFID tag and enhances antenna gain without the need for a dedicated antenna, allowing for flexible frequency adjustment by modifying the resonant circuit or matching circuit.
Implementation Method 1
a response signal from the wireless IC (chip) is radiated from the electrode to the outside via the loop electrode
Implementation Method 2
the power supply circuit board includes a resonant circuit and/or a matching circuit including an inductance element, and the frequency used is substantially set by the resonant circuit and/or the matching circuit
Data Source
Figure 1(A)~2
Figure 3(A)~3(B)
Figure 4(A)~4(B)
AI summary
A wireless IC device and an electronic apparatus are obtained, which can achieve miniaturization and improve the gain of a radiator plate (electrode) without providing a dedicated antenna. A wireless IC device is provided, in which a loop electrode (31) is provided in a ground electrode (21) provided on a printed wiring circuit board (20), and in which a wireless IC chip (5) that processes a transmission/reception signal or an electromagnetic coupling module (1) is coupled to the loop electrode (31). The ground electrode (21) is coupled to the wireless IC chip (5) or the electromagnetic coupling module (1) via the loop electrode (31), and transmits or receives a high-frequency signal. The ground electrode (21) is formed with a slit (23a), (23b) for adjusting a resonant frequency thereof.