Wireless Tag Choke Filter for Antenna Interference
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Solution Overview
Problem
Large metal structures connected to the ground in wireless tags interfere with the antenna's performance due to their interaction with the surrounding material, particularly in single-layer substrate designs, affecting the tag's operation.
Innovation Solution
A filter, such as a choke, is electrically interposed between the chip and conductive structures to cause an electrical disconnection at specific frequencies, reducing the impact of these structures on the antenna, effectively acting as a narrowband filter to disconnect the chip from metal structures at frequencies like 2.4 GHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large metal structures are used in wireless tags, then the tag can provide necessary electrical connections and grounding, but the metal structures interfere with antenna performance and affect tag operation
Solution Approach 1:
The patent segments the electrical connection between the chip and ground by inserting a filter circuit. This filter divides the direct electrical path into separate components (capacitor and inductor elements) that can selectively block harmful frequencies while maintaining necessary electrical connections for tag operation.
Solution Approach 2:
The filter circuit acts as an intermediary element between the chip and the ground connection. It mediates the electrical interaction by allowing DC and low-frequency signals to pass while blocking high-frequency RF interference, thus protecting the antenna system without compromising the grounding function.
2Stability of the object's composition
If conductive structures are connected directly to ground for electrical stability, then the chip has reliable electrical connection, but the connection path allows interference to affect antenna performance
Solution Approach 1:
The patent applies local quality modification by making the electrical connection frequency-dependent. The filter provides different electrical characteristics at different frequencies: low impedance at DC and low frequencies for stability, and high impedance at RF frequencies to block interference.
Solution Approach 2:
The filter circuit changes the electrical parameters (impedance, conductivity) of the connection path based on frequency. By using reactive components with frequency-dependent characteristics, the connection maintains stability for signal processing while blocking harmful RF interference.
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 filter significantly reduces the interference between the conductive structures and the antenna, enhancing the wireless tag's performance by acting as an open circuit at the desired frequency, thereby improving the tag's operational efficiency.
Implementation Method 1
a filter electrically interposed along an electrical connection between the chip and the conductive structure; wherein the filter causes an electrical disconnection between the conductive structure and the chip at around a prescribed frequency
Implementation Method 2
a choke electrically interposed along an electrical connection between the chip and the conductive structure; wherein the choke acts as a filter to cause a reduction in amplitude of a signal passing between the conductive structure and the chip at around a prescribed frequency
Data Source
AI summary
A wireless tag comprises a chip; an antenna; at least one conductive structure, the conductive structure and the chip being coupled by a common electrical connection to ground; and a filter electrically interposed along an electrical connection between the chip and the conductive structure; wherein the filter causes a reduction in amplitude of a signal passing between the conductive structure and the chip or an electrical disconnection between the conductive structure and the chip at around a prescribed frequency.