Backscatter RFID Transponder Beamforming for Range and Orientation
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Solution Overview
Problem
Current RFID systems face limitations in range, orientation determination, and multipath propagation, leading to performance degradation and increased hardware complexity, especially in complex electromagnetic environments, which restricts their application in scenarios like logistics and intelligent warehouses.
Innovation Solution
The use of a transponder with a backscatter-type antenna configuration, featuring multiple antennas with controllable phase offsets and modulation frequencies, enabling beamforming and focusing to increase directivity and range, while reducing hardware complexity on the reader side and mitigating multipath effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If omnidirectional antenna configuration is used to cover large spatial sector, then coverage area is improved, but directivity and range are degraded
Solution Approach 1:
The patent implements dynamic beamforming capabilities that allow the antenna system to adapt its radiation pattern in real-time. The reader can electronically steer and focus beams toward specific tags, transitioning from a static omnidirectional pattern to dynamic directional patterns as needed for different operational scenarios.
Solution Approach 2:
The invention applies local quality by creating focused high-gain beams in specific spatial directions rather than uniform omnidirectional radiation. The system concentrates electromagnetic energy locally toward target tags, improving signal strength and range in those specific directions while maintaining the ability to cover multiple sectors through beam steering.
2Length of moving object
If directional antenna configuration is used to increase range, then communication range is improved, but spatial coverage is reduced
Solution Approach 1:
The system dynamically switches between omnidirectional and directional modes, and can electronically scan through multiple directional beams to cover different spatial sectors. This allows the system to achieve both long range (when focused on a specific tag) and broad coverage (when scanning through multiple directions or using omnidirectional mode for initial acquisition).
Solution Approach 2:
The antenna system is designed to perform multiple functions: omnidirectional coverage for initial tag acquisition, directional beamforming for extended range communication, and scanned beam patterns for spatial mapping. This multi-functionality allows a single system to address both coverage and range requirements.
3Measurement precision
If MIMO concepts are used to evaluate angle information, then orientation determination is improved, but system complexity is increased
Solution Approach 1:
The patent introduces a signal processing intermediary layer that extracts orientation information from backscatter signals. Instead of requiring complex MIMO hardware, the system uses sophisticated signal processing algorithms to analyze phase and amplitude variations in the backscattered signals, thereby determining tag orientation through software-based intermediaries rather than hardware complexity.
Solution Approach 2:
The invention replaces complex physical MIMO antenna arrays with a simpler single-antenna or reduced-antenna system that uses signal processing techniques to achieve similar orientation determination capabilities. This substitutes mechanical/electromagnetic system complexity with computational processing.
4Use of energy by moving object
If backscatter modulation is used to achieve power efficiency, then power consumption is reduced, but hardware complexity shifts to reader side
Solution Approach 1:
The patent extracts the RF carrier generation function from the tag and relocates it to the reader. The tag only needs to modulate and backscatter the incoming carrier signal, which dramatically reduces tag power consumption. The reader assumes the burden of generating and managing the RF carrier, thereby extracting the power-intensive function from the constrained tag device.
5Adaptability or versatility
If standard backscatter tag with omnidirectional radiation is used, then orientation independence is improved, but range and directivity are degraded
Solution Approach 1:
The system dynamically adapts its radiation pattern based on the operational phase. During initial acquisition, it uses omnidirectional or wide-beam patterns for orientation independence. Once a tag is detected, it transitions to narrow, focused beams for extended range communication, thereby dynamically balancing orientation independence with range requirements.
Solution Approach 2:
The reader performs periodic omnidirectional scanning or wide-beam sweeping to maintain awareness of tag positions and orientations in the environment. This periodic omnidirectional action ensures orientation independence for tag detection, while between these periodic scans, the system uses focused directional beams for sustained high-range communication with detected tags.
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 configuration enhances the range and directivity of RFID communication, allows for accurate orientation and position determination, and reduces the impact of multipath propagation, resulting in a more robust and cost-effective system capable of handling multiple tags and complex environments.
Implementation Method 1
The tag is based on backscatter (BS) antenna base modulation. Instead of generating the RF carrier in the tag, the RF carrier generated in the reader is reused, modulated and reflected in a controlled manner.
Implementation Method 2
The use of a transponder with a backscatter-type antenna configuration, featuring multiple antennas with controllable phase offsets and modulation frequencies, enabling beamforming and focusing to increase directivity and range
Implementation Method 3
at least a first line is formed by at least one first and at least one second antenna, each configured and operated in the backscatter type, and functionally connected to one another in such a way that when a signal is received, they backscatter the signal in the backscatter type by means of shaped radiation characteristics
Data Source
Figure 1
AI summary
The invention relates to a transponder, wherein at least one first line is formed by at least one first and at least one second antenna configured and operated in the manner of a backscatter, which antennas are connected to one another in such a way that upon reception of a signal the antennas scatter the signal back in the manner of a backscatter by a formed emission characteristic. The invention further relates to a method for operating the transponder.