Packaged RFID IC with Integrated Coil Antenna
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Solution Overview
Problem
Conventional RFID tag manufacturing processes face challenges with mechanical damage and thermally induced failures due to exposed RFID ICs and difficulties in integrating inductive tuning elements, especially in slot antenna designs, leading to compromised antenna designs or costly inductors.
Innovation Solution
A precursor comprising an RFID IC coupled to a conductive coil formed from multiple lead-frame segments, where the coil acts as an inductive tuning element and is encapsulated in a non-conductive material, providing protection and compatibility with standard lead-frame-based package construction, allowing for either standalone or external antenna configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the RFID IC is exposed and connected to the antenna using conductive epoxy, then the manufacturing process is simple, but the RFID IC is vulnerable to mechanical damage and thermally induced failures
Solution Approach 1:
The patent merges the RFID IC, the inductive tuning element, and the encapsulation into a single integrated package. The lead frame segments are formed into a coil structure that serves as both the inductive tuning element and part of the antenna, eliminating the need for separate components and connections. This integration protects the RFID IC from mechanical damage and thermal failures while maintaining manufacturing efficiency through standard lead-frame-based processes.
Solution Approach 2:
The RFID IC is nested within the encapsulation material, which is in turn attached to the lead frame. The lead frame segments are folded and connected to form a coil that surrounds and protects the RFID IC. This nested structure provides mechanical protection and thermal isolation while maintaining electrical connectivity through the encapsulation material.
2Reliability
If conventional matching circuits use a conductive loop as part of the antenna, then the tuning function is achieved, but it is difficult to build the loop into slot antennas, resulting in compromised antenna designs or costly inductors
Solution Approach 1:
The patent combines the inductive tuning element with the antenna structure by forming the lead frame segments into a coil that serves dual purposes: providing the necessary inductance for matching and acting as part of the radiating antenna structure. This eliminates the need for separate inductors or compromised antenna designs, particularly for slot antennas where integrating discrete inductors would be complex and costly.
Solution Approach 2:
The lead frame coil structure serves multiple functions simultaneously: it provides mechanical support, acts as the inductive tuning element for impedance matching, and functions as part of the antenna radiating structure. This multi-functionality simplifies the overall antenna design and reduces the number of separate components needed.
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 enhances the reliability and cost-effectiveness of RFID tags by encapsulating the RFID IC and tuning element, reducing mechanical vulnerabilities and eliminating the need for external antennas in short-range applications, while maintaining compatibility with existing manufacturing processes.
Implementation Method 1
The terminals of an RFID IC typically expose an input which is capacitive, and which must be compensated by an inductive tuning element at an operating frequency of the tag
Implementation Method 2
The reader transmitting a Radio Frequency (RF) wave performs the interrogation. The RF wave is typically electromagnetic, at least in the far field.
Implementation Method 3
The tag generates the transmitted back RF wave either originally, or by reflecting back a portion of the interrogating RF wave in a process known as backscatter
Data Source
AI summary
A precursor for a Radio Frequency Identification (RFID) tag includes a conductive lead frame with at least three segments, an RFID Integrated Circuit (IC) with at least two antenna terminals, and at least two jumpers. The RFID IC is mounted on at least one of the segments. The antenna terminals are electrically coupled to at least two of the segments, and the jumpers electrically couple the segments such that the coupled segments form a two-turn coil between the antenna terminals of the RFID IC.