UHF and mm-wave RFID Localization via Beam Steering
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Solution Overview
Problem
Passive RFID systems using UHF wireless signaling face challenges in accurate localization of objects, with location accuracy limited to the order of the UHF wavelength, typically around 33 cm, which is insufficient for precise tracking applications.
Innovation Solution
The integration of UHF and mm-wave RFID systems, where a UHF reader device transmits signals in one frequency band and uses miniature mm-wave transmitters to generate beams that are steered to detect signal strength, allowing for accurate localization by determining the orientation and distance of RFID transponders through spatial LMS interpolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If UHF RFID systems are used for object detection and identification, then the detection range is extended to several meters and shelf life is improved, but location accuracy deteriorates to only about 33 cm
Solution Approach 1:
The patent combines UHF RFID technology with mm-wave beam steering technology into an integrated system. The UHF RFID transponder provides identification and basic detection, while the mm-wave transmitters provide precise localization through beam steering. This merging of two different frequency band technologies resolves the contradiction by allowing the system to maintain the long shelf life advantage of passive UHF RFID while achieving centimeter-level location accuracy through mm-wave beam orientation detection.
2Length of stationary object
If UHF RFID systems are used for localization, then detection range is improved to several meters, but location accuracy deteriorates to the order of UHF wavelength
Solution Approach 1:
The patent introduces a new dimension of measurement by using mm-wave beam steering in addition to the traditional UHF RFID detection. Instead of relying solely on UHF signal strength for localization, the system uses the orientation information from mm-wave beam steering to determine precise angular position. This dimensional addition allows the system to maintain extended detection range while achieving superior location accuracy.
3Measurement precision
If mm-wave transmitters are integrated with UHF reader to achieve accurate localization, then location accuracy is improved to about 5 cm, but device complexity increases
Solution Approach 1:
The integrated reader device performs multiple functions: it operates as a traditional UHF RFID reader for identification and detection, while simultaneously functioning as an mm-wave beam steering system for precise localization. This multi-functionality reduces the need for separate dedicated systems and allows a single device to achieve both identification and high-precision localization, thereby managing complexity while improving accuracy.
4Duration of action of stationary object
If passive RFID devices are used, then battery power is eliminated extending shelf life, but localization accuracy deteriorates due to lack of active transponding
Solution Approach 1:
The passive RFID transponder harvests energy from the incident UHF RFID signals to power its circuitry and enable it to respond to the reader's queries. This self-powered operation eliminates the need for batteries while maintaining the ability to provide identification and basic detection functions. When combined with the mm-wave beam steering capability, the system achieves accurate localization without requiring active battery-powered transponders.
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 enables pinpoint localization of RFID transponders with an accuracy of about 5 cm, significantly improving upon the limitations of UHF-only systems by combining UHF identification with mm-wave beam steering for precise tracking and positioning.
Implementation Method 1
Passive RFID (radio frequency identification) devices, based on UHF (ultra-high frequency; 300 MHz-3 GHz) wireless signaling, allow detection and identification of objects
Implementation Method 2
uses miniature mm-wave transmitters to generate beams that are steered to detect signal strength
Implementation Method 3
allowing for accurate localization by determining the orientation and distance of RFID transponders through spatial LMS interpolation
Data Source
AI summary
A method includes: transmitting, from a reader device, a first set of wireless signals, in a first frequency band, detectable by RFID transponder devices; transmitting, from the reader device, a second set of wireless signals, at a second frequency band different from the first frequency band, detectable by the RFID transponder devices; detecting, at the reader device, a set of reply wireless signals transmitted by one or more of the RFID transponder devices in response to the first set of wireless signals, the set of reply signals comprising identification data associated with the one or more of the RFID transponder devices, and orientation information representative of relative orientation of the respective one or more of the RFID transponder devices to the reader device; and deriving location information for at least one of the one or more of the RFID transponder devices based on the detected set of reply wireless signals.