SAW Transponder Real-Time 3D Tracking
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Solution Overview
Problem
Existing tracking systems for objects in three-dimensional space are cumbersome, costly, and limited by environmental interference, bandwidth, and accuracy, particularly when attempting to track multiple objects in real-time with high data rates.
Innovation Solution
The use of surface acoustic wave (SAW) transponders that receive electromagnetic interrogation signals, convert them into surface acoustic waves, and return encoded signals without electronic processing, allowing for accurate three-dimensional tracking with minimal size, cost, and power consumption, enabling high tracking rates and resistance to environmental interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If active RFID tags with batteries are used, then tracking range is extended, but device size and cost increase
Solution Approach 1:
The patent replaces electronic signal processing circuits with surface acoustic wave (SAW) devices that use mechanical acoustic waves to encode and modulate signals. This substitution eliminates the need for complex electronic circuitry and batteries, achieving miniaturization while maintaining tracking capability through the SAW device's ability to process signals mechanically rather than electronically
Solution Approach 2:
The patent changes the operating parameters by using surface acoustic waves instead of traditional electromagnetic signals for signal processing. The SAW devices operate at specific frequencies and use the mechanical properties of the substrate to achieve signal modulation, thereby reducing power requirements and device size while extending operational range
2Volume of moving object
If passive RFID tags without batteries are used, then device size is reduced, but response time increases and tracking speed decreases
Solution Approach 1:
The patent employs surface acoustic waves that propagate as mechanical vibrations across the substrate surface. These vibrations enable rapid signal transmission and processing without the delays associated with electronic signal generation, thereby reducing response time while maintaining the passive, battery-less design of the transponder
3Loss of information
If complex solid-state electronic circuitry is used in transponders, then signal processing capability is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent replaces complex solid-state electronic circuitry with surface acoustic wave devices that use mechanical wave propagation for signal processing. The SAW devices encode and modulate signals through the mechanical vibration and reflection of acoustic waves, eliminating the need for complex electronic components while maintaining signal processing capability
Solution Approach 2:
The patent extracts and removes the complex electronic signal processing circuitry from the transponder design, retaining only the essential SAW device components. This extraction simplifies the device structure and manufacturing while preserving the ability to process and encode signals through acoustic wave mechanisms
4Reliability
If ultrasonic transponders are used, then tracking capability is achieved, but device bulkiness and environmental sensitivity increase
Solution Approach 1:
The patent changes the operating parameters by using surface acoustic waves at specific frequencies that are less susceptible to environmental interference compared to traditional ultrasonic waves. The SAW devices operate on the surface of a substrate, isolating them from environmental factors, thereby maintaining tracking capability while reducing device bulkiness and environmental sensitivity
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 SAW transponder system provides accurate, real-time tracking of multiple objects in three-dimensional space with high data rates, overcoming the limitations of existing technologies by being small, inexpensive, and capable of functioning in the presence of environmental interference.
Implementation Method 1
The conductive element converts the electrical energy received by the antenna into a surface acoustic wave that propagates across the surface of the substrate where it is intercepted by a pattern of encoding elements on the substrate
Implementation Method 2
the conductive element converts the reflected acoustic energy into a delayed and modified electromagnetic response signal that is applied to and transmitted by the SAW device antenna
Data Source
AI summary
A system for tracking the position of multiple objects in three dimensional space by transmitting radar interrogation signals having predetermined wave shapes to surface acoustic wave transducers attached to each object. Each transducer includes a unique electrically conductive pattern on one surface of a piezoelectric substrate for selectively responding to the predetermined wave shape of one of the interrogation signals for inducing a surface acoustic wave in the substrate and for thereafter transforming the surface acoustic wave into an electromagnetic response signal having detectable properties that uniquely identify said transducer. The location of each transducer is estimated by measuring the time-of-flight or angle-of-arrival of the radar signals at several measurement stations and producing a position estimate by triangulation.