UWB RFID Backscatter Modulator for Multipath Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current RFID systems based on narrow bandwidth backscatter modulation have limited read/write operating range, are prone to interference, and lack accurate localization and security, making them unsuitable for applications requiring centimeter precision and robustness against multipath signals and interference.
Innovation Solution
The method involves generating an ultra-wide bandwidth signal with a sequence of equally spaced pulses, using numerical coding to ensure all pulses in a period have the same polarity for backscatter modulation, and employing a backscatter modulator with switches to isolate the antenna mode component from structural and clutter components, allowing robust communication and accurate data detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If narrow bandwidth backscatter modulation is used in RFID systems, then device complexity and cost are reduced, but communication reliability and anti-interference capability deteriorate due to multipath effects and shadowed zones
Solution Approach 1:
The patent changes the bandwidth parameter from narrow to ultra-wideband (UWB), transforming the signal characteristics to achieve superior multipath resolution and communication reliability while maintaining passive tag operation. The UWB signal's large time-bandwidth product enables accurate resolution of multipath components that would otherwise create shadowed zones and interference.
2Use of energy by moving object
If narrow bandwidth signals are used for RFID communication, then energy consumption is reduced, but localization precision and temporal resolution deteriorate to insufficient levels for centimeter accuracy
Solution Approach 1:
The patent transforms the signal bandwidth parameter to ultra-wideband, which provides extraordinary precision in distance estimation based on time-of-arrival measurement. The large time-bandwidth product of UWB signals enables centimeter-level localization accuracy while maintaining low energy consumption through passive operation and low duty cycle transmission.
3Quantity of substance
If passive tags operate with narrow bandwidth backscatter modulation, then cost and size are minimized, but the maximum number of contemporaneously addressable tags is strongly limited by low transmission data rate and high interference probability
Solution Approach 1:
The patent changes the bandwidth parameter to ultra-wideband, which dramatically increases the transmission data rate capability. This enables a much larger number of tags to be addressed contemporaneously by the reader, overcoming the severe limitation of narrowband systems where high interference probability and low data rates restrict the addressable tag population.
4Device complexity
If narrow bandwidth RFID systems operate in environments with signal reflections, then device simplicity is maintained, but destructive interference creates shadowed zones and reduces system reliability
Solution Approach 1:
The patent converts the harmful multipath reflections into a beneficial resource by using UWB's superior time resolution to separate and identify individual multipath components. Instead of creating shadowed zones through destructive interference, the system resolves each reflection path separately, using the temporal resolution to distinguish direct paths from reflected paths and eliminate their harmful effects.
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 enhances communication robustness against environmental reflections, eliminates antenna structural dependent components, and achieves reliable data detection with low power consumption, enabling accurate localization and secure, high-density tag management.
Implementation Method 1
passive or semi-passive RFID devices with electromagnetic coupling
Implementation Method 2
the tag modulates, through the control of the antenna's impedance (backscatter modulation), the reflected power (backscatter)
Data Source
AI summary
A method for communication in ultra-wide bandwidth RFID systems comprising generating through a transceiver device an interrogated signal, composed of at least a sequence of equally time spaced pulses with period (T3), transmitting said signal to at least one RFID identification device which generates a response signal and transmits it back to said transceiver device, said method further comprising coding said interrogation signal according to a numerical coding sequence, generating said response signal by varying, in each period (T3) of said pulse sequence of the interrogation signal, the polarity of pulses using said numerical coding sequence. An apparatus for communication in ultra-wide bandwidth RFID systems comprising a transceiver device (1,101) and a RFID identification device (11), suitable for communicating each other, said RFID identification device (11) comprises a backscatter modulator (12) suitable for modulating a signal reflected by an antenna (18) of the identification device RFID.