Multi-Beam Antenna for Directional RFID Localization
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Solution Overview
Problem
Existing RFID systems face challenges in accurately determining the direction of transponders due to limitations in signal processing, particularly with RSSI-based methods that rely on amplitude measurements without phase information, leading to low directional accuracy and high installation costs.
Innovation Solution
A device with a multi-cheacut antenna and a feeding network, such as a Butler matrix, separates signals into individual directional characteristics, allowing for the evaluation of signal amplitude and phase, and alternately connects signal outputs to an information reading device and data processing device for precise direction determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RSSI-based methods are used for direction determination, then the system can operate with simple amplitude measurements, but the directional accuracy becomes low due to lack of phase information
Solution Approach 1:
The patent changes the measurement parameters from amplitude-only (RSSI) to include both amplitude and phase information. By utilizing the phase component of the received signals in addition to amplitude, the system achieves higher directional accuracy without requiring complex hardware modifications, thus resolving the contradiction between measurement precision and device complexity.
2Measurement precision
If multiple antennas are distributed spatially to improve direction information, then directional accuracy improves, but the space requirement and installation effort increase
Solution Approach 1:
The patent combines multiple antenna elements into a compact array configuration with a feeding network (such as a Butler matrix). This merging approach allows the system to achieve the directional accuracy benefits of multiple spatially distributed antennas while maintaining a compact physical footprint, thus reducing installation space and effort while preserving measurement precision.
3Measurement precision
If phase information is extracted from antenna signals to improve direction determination, then directional accuracy improves, but typical RFID readers cannot provide this capability as they only offer amplitude measurements
Solution Approach 1:
The patent introduces a feeding network (such as a Butler matrix or other beamforming network) as an intermediary between the antenna array and the standard RFID reader. This intermediary component performs the phase information extraction and signal processing functions, allowing the use of conventional RFID readers that only provide amplitude measurements while still achieving phase-based directional accuracy. The feeding network acts as a mediator that bridges the capability gap between simple readers and complex directional requirements.
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 solution provides accurate and reader-independent localization, reducing installation costs and improving directional estimation by utilizing multiple directional characteristics for enhanced sensitivity and phase information analysis.
Implementation Method 1
The antenna device has a feeding network, whereby the feeding network causes different directional characteristics of the antenna device and separates signals received with the antenna device into the individual directional characteristics
Implementation Method 2
these transponders are passive and are stimulated by a high-frequency electromagnetic field. The transponder uses this signal and sends a modulated signal back to the RFID reader in response to the excitation
Data Source
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AI summary
The invention relates to a device (1) for determining an item of information regarding a position of a transmitter (2), comprising an antenna device (3), a control device (4) and a data processing device (5). The antenna device (3) has a plurality of different directional characteristics (9), each of which refers to an amount of spatially different reception sensitivities of the antenna device (3). The antenna device (3) has signal outputs (10), wherein the directional characteristics (9) are associated with the signal outputs (10). The control device (4) connects a signal output (10) of the antenna device (3) with an information reading device (6) and further signal outputs (10) of the antenna device (3) with the data processing device (5). The information reading device (6) determines data from received signals and transmitted by said signals. The data processing device (5) evaluates received signals with regard to their physical properties. The invention further relates to a corresponding method.