Wireless Interrogation Device for SAW Components
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Solution Overview
Problem
Current methods for wireless interrogation of surface wave components operating according to the delay line principle suffer from significant measurement errors due to parasitic couplings and 1/f noise, which cannot be effectively eliminated, leading to inaccuracies of several percent, even with complex and costly shielding measures.
Innovation Solution
A method and device that use a second high frequency signal derived from the same frequency reference as the excitation signal but differing from it, to generate a control signal and bandpass-filter both the data and control signals, achieving digital coherence and reducing errors by separating parasitic effects, allowing for a simpler and more accurate data extraction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If homodyne detection is used with a single high frequency signal for exciting and receiving, then the device structure is simple, but measurement precision deteriorates due to parasitic couplings and 1/f noise
Solution Approach 1:
The patent divides the single high frequency signal into two separate signals: a first high frequency signal for exciting the SAW component and a second high frequency signal (at a different frequency) for receiving. This segmentation allows the transmission and reception paths to be independent, eliminating parasitic couplings while maintaining relatively simple device structure.
Solution Approach 2:
The patent introduces an intermediary mixing process where the response signal is mixed with the second high frequency signal (different from the excitation frequency). This intermediary step separates the useful signal from parasitic couplings and 1/f noise, enabling accurate measurement without complex shielding measures.
2Measurement precision
If complex shielding measures are implemented to eliminate parasitic couplings, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates parasitic couplings by using frequency separation. The first high frequency signal (for excitation) and second high frequency signal (for reception) operate at different frequencies, which allows the system to distinguish and extract the useful response signal from parasitic interference without requiring physical shielding measures.
Solution Approach 2:
The patent changes the frequency parameter of the signals used for reception. By using a second high frequency signal that differs from the first excitation frequency, the system transforms the reception process into a frequency-domain separation problem, which can be solved through signal processing rather than complex physical shielding.
3Device complexity
If the same frequency signal is used for both excitation and reception, then the device structure is simple, but measurement precision deteriorates due to 1/f noise
Solution Approach 1:
The patent segments the single frequency signal into two different frequencies: the first high frequency signal for excitation and the second high frequency signal for reception. This frequency segmentation allows the system to differentiate between the excitation signal and the response signal, eliminating 1/f noise interference while maintaining simple device structure.
Solution Approach 2:
The patent introduces an intermediary mixing process where the response signal is mixed with the second high frequency signal (different from the excitation frequency). This intermediary step separates the useful signal from 1/f noise, enabling accurate measurement without complex shielding measures.
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 solution significantly reduces measurement errors, enabling more accurate data extraction with improved accuracy and reduced susceptibility to errors, allowing for a simpler and cost-effective interrogation device design.
Implementation Method 1
the response signal is received and mixed with a reference signal in a mixer and a data signal is generated in the process
Implementation Method 2
the data signal is bandpass-filtered in analog form, that the filtered data signal and the control signal are converted to a digital signal
Implementation Method 3
the data signal is bandpass-filtered in analog form
Data Source
AI summary
A method for wireless interrogation of data from a passive element. A first high frequency signal sent to the element excites the element to transmit a response signal which is received and mixed with a reference signal in a mixer, generating a data signal. The data signal is evaluated to extract data. A second high frequency signal generated from the same frequency reference as the first frequency signal is used as a reference signal. A control signal is generated by mixing the reference and first frequency signals. The data signal is bandpass-filtered in analog form and is converted, with the control signal, to a digital signal and digital control signal which are then each bandpass-filtered in digital form. The digital data and digital control signals are correlated to form a result signal so that a digital coherence is achieved. Raw data representing the data are obtained from the result signal.