Millimeter-Wave RFID Beam Switching for Far-Field Tag Powering
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Solution Overview
Problem
Existing RFID technologies face challenges in powering and communicating with small, chip-less RFID tags in IoT applications, due to size constraints that limit their use in far-field environments and require near-field coupling, which restricts their operational range.
Innovation Solution
A multimode millimeter wave RFID system that uses a radiofrequency device with an antenna array to transmit and receive electromagnetic radiation, capable of operating in both SAR mode for imaging and locating RFID tags, and communications mode for powering and communicating with them in far-field environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If magnetic or capacitive near-field coupling is used to power and communicate with small RFID tags, then the tags can be powered without local power sources, but the operational distance is limited to less than a few centimeters
Solution Approach 1:
The reader device is designed to perform multiple functions: near-field coupling for powering small RFID tags and far-field beam transmission for powering and communicating with IoT devices. This multi-functionality allows the system to adapt to different device sizes and operational requirements, breaking the distance limitation for small tags while maintaining the ability to power larger devices at greater distances
Solution Approach 2:
The system dynamically switches between near-field and far-field operational modes based on the target device characteristics. The reader can adjust its transmission mode and power level to optimize performance for either small RFID tags requiring near-field coupling or larger IoT devices that can be powered and communicated with using far-field directional beams
2Volume of moving object
If RFID tags are made small for IoT applications, then they can be integrated into various objects, but antennas cannot be placed on the tags and far-field operation becomes impossible
Solution Approach 1:
The reader device acts as an intermediary that provides external antenna functionality. Instead of requiring antennas on the small RFID tags themselves, the reader device supplies the necessary antenna functions through its own antenna system, enabling small tags to operate in far-field environments by receiving power and signals through the reader's transmitted beams
Solution Approach 2:
The reader device is designed with universal capability to support both traditional RFID tags with antennas and small IoT devices without antennas. It can operate in near-field mode for tags requiring close coupling and in far-field mode for antennaless IoT devices, making the system adaptable to diverse application scenarios regardless of device size
3Ease of manufacture
If SAR or backscatter technology is used for chip-less RFID tags, then communication is enabled without ICs, but the system is limited to readers employing only those specific technologies
Solution Approach 1:
The reader device is designed with multi-functional capability to support multiple RFID technologies: SAR mode for chip-less tags, backscatter mode for traditional passive tags, and direct communication mode for IoT devices with local processors. This universality allows a single reader system to interrogate and communicate with diverse tag types without requiring separate specialized readers for each technology
Solution Approach 2:
The system dynamically adjusts its operational mode based on the detected tag type. It can switch between SAR imaging mode, backscatter communication mode, and direct far-field communication mode to optimize performance for different tag configurations, making the reader adaptable to various RFID implementations
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 system enables accurate location and communication with various types of RFID tags and IoT devices, overcoming the limitations of near-field coupling and extending the operational range to support diverse applications, including inventory management, asset tracking, and healthcare identification.
Implementation Method 1
A radiofrequency device with an antenna array is configured to transmit and receive electromagnetic radiation
Implementation Method 2
A spatial location for one or more RFID tags located within the scanned area is determined from a radar image generated based on reflected radiofrequency beams from the scan area and re-radiated radiofrequency beams from the one or more RFID tags
Implementation Method 3
Instead, magnetic or capacitive near-field coupling must be used to power and communicate with the RFID tag
Implementation Method 4
magnetic or capacitive near-field coupling must be used to power and communicate with the RFID tag
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A radiofrequency identification (RFID) reader device includes a radiofrequency device configured to transmit and receive electromagnetic radiation through an antenna array. An RFID control computing device is coupled to the radiofrequency device and includes a memory coupled to a processor which is configured to be capable of executing programmed instructions comprising and stored in the memory to operate the radiofrequency device in a first mode to transmit a first radiofrequency beam to a scan area through the antenna array. A spatial location for RFID tags located within the scanned area is determined from a radar image. The radiofrequency device is operated in a second mode to transmit a second radiofrequency beam to at least one of the RFID tags, based on the determined spatial location of the RFID tags, to power an integrated circuit or sensor located on and to communicate with the at least one of the RFID tags.