Twin-IC RFID Tag Layout for Omnidirectional Radiation Without Nulls
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Solution Overview
Problem
Conventional RFID tags using two-pad RF chips generate a radiation pattern with a null, which are not cost-effective compared to four-pad chips, necessitating a novel design to achieve an omnidirectional radiation pattern without a null at a lower cost.
Innovation Solution
A twin IC structure comprising two adjacent RF chips, each with two pads, connected via wirings to complementary antennas, forming a cross-polarized dipole configuration to eliminate nulls and achieve omnidirectional radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a four-pad RF chip is used, then an omnidirectional radiation pattern without null is achieved, but the cost increases
Solution Approach 1:
The patent divides a single four-pad RF chip into two separate two-pad RF chips. Each two-pad chip is connected to one complementary antenna, creating two independent radiation patterns that combine to form an omnidirectional pattern without nulls. This segmentation allows the use of cheaper two-pad chips while achieving the performance of a four-pad chip.
Solution Approach 2:
The patent combines the radiation patterns from two separate two-pad RF chips and their associated complementary antennas to create an omnidirectional radiation pattern. By merging the electromagnetic fields from both chips, the system achieves the same radiation characteristics as a four-pad chip would provide alone.
2Ease of manufacture
If a two-pad RF chip is used, then the cost is reduced, but the radiation pattern contains a null
Solution Approach 1:
The patent employs complementary antennas with asymmetric orientations (one horizontal, one vertical) to compensate for the limitations of two-pad chips. The asymmetric configuration ensures that the radiation patterns from both chips combine constructively in all directions, eliminating nulls while maintaining cost effectiveness.
Solution Approach 2:
The patent transitions from a single-plane radiation pattern to a three-dimensional omnidirectional pattern by using complementary antennas oriented in different dimensions (horizontal and vertical). This dimensional approach allows two-pad chips to achieve omnidirectional coverage that would otherwise require four pads in a single plane.
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 twin IC design achieves an omnidirectional radiation pattern without nulls, reducing costs by using two-pad chips, comparable to the performance of four-pad chips, and is applicable to high and ultra-high frequency RFID tags.
Implementation Method 1
each of the first RF chip and the second RF chip has two pads. The two pads of the first RF chip and the two pads of the second RF chip are connected to two complementary antennas
Implementation Method 2
forming a cross-polarized dipole configuration to eliminate nulls and achieve omnidirectional radiation
Data Source
AI summary
A RFID tag that includes a first RF chip, a second RF chip, a first wiring and a second wiring is provided. The first RF chip and the second RF chip are adjacent and connected to each other, and each of the first RF chip and the second RF chip has two pads. Said two pads of the first RF chip and said two pads of the second RF chip are connected to two complementary antennas. The first wiring conducts said two pads of the first RF chip to one of said two complementary antennas. The second wiring conducts said two pads of the second RF chip to the other of said two complementary antennas.