Interdigitated RFID Antenna Feed for Chip Alignment
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Solution Overview
Problem
Current RFID tag manufacturing techniques are costly and inefficient for producing item-level tags, particularly due to the high expense of integrated circuits and challenges in mounting small chips onto antennas, leading to high failure rates and increased costs per unit.
Innovation Solution
The use of interdigitated antenna feeds with probabilistic chip placement methods, such as direct DC contact, magnetic/electric alignment, and field coupling, allows for the efficient connection and alignment of microradio-sized integrated circuits to antennas, eliminating the need for pick-and-place machines and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pick-and-place machine methods are used to mount integrated circuits to antennas, then manufacturing precision can be achieved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The antenna structure itself provides the alignment and mounting function through its geometric features. The antenna includes a first portion with a first geometric feature and a second portion with a second geometric feature that corresponds to the chip's first and second ends, enabling self-alignment and self-mounting without external pick-and-place machinery.
Solution Approach 2:
The antenna is divided into multiple portions (first portion and second portion) with corresponding geometric features that match the chip's ends. This segmentation allows the chip to be mounted by simply placing it on the antenna, with each portion providing specific alignment functions independently.
2Reliability
If larger antennas are used to increase reading range, then energy capture improves, but the tag size and complexity increase
Solution Approach 1:
The chip is positioned within the antenna structure itself, with the chip's geometric features nested within corresponding features of the antenna portions. This integration allows the antenna to maintain sufficient size for long-range operation while minimizing the overall tag footprint by eliminating separate mounting structures.
3Productivity
If multiple chips are mounted on a single antenna, then productivity increases, but manufacturing precision requirements become more stringent
Solution Approach 1:
The antenna is segmented into multiple portions, each with geometric features designed to receive specific chips. This segmentation provides independent mounting zones for multiple chips, allowing each chip to be positioned and aligned independently without requiring high precision across the entire antenna structure.
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 significantly reduces the cost of RFID tags by enabling the production of millions of chips on a single wafer, achieving a high yield and reliable connection of small integrated circuits to antennas, thereby lowering the overall price per tag while ensuring efficient energy transfer and data transmission.
Implementation Method 1
The antenna transfer RF energy to the integrated circuit
Implementation Method 2
the energy being derived from a so-called rectenna that rectifies the RF energy and stores it on a capacitor
Implementation Method 3
this assembly is then positioned at the appropriate region of the main antenna, preferably a narrowed region that concentrates magnetic fields surrounding the chip
Data Source
AI summary
A method for mounting multiple small RFID chips onto larger antenna. The chips are mechanically aligned with an interdigitated gap at the feed point of the antenna by electrostatic or magnetic techniques. In an alternate embodiment RF field coupling between the chips and the antenna is employed.