Wall Detector Depth Resolution via Permittivity Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wall detection systems face challenges in accurately determining the depth of objects within substrates due to variations in substrate permittivity caused by humidity and salt content, leading to inefficient power usage and reduced measurement depth.
Innovation Solution
A wall detector system that includes a detection antenna for introducing broadband high-frequency electric fields, a measurement system for detecting object depth, and a permittivity measurement device with an auxiliary potential plate to measure permittivity at a lower frequency, allowing for accurate determination of substrate permittivity and object depth using a material model.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high measurement frequency is used to improve depth resolution, then depth resolution is improved, but measurement depth and penetration are reduced due to higher attenuation
Solution Approach 1:
The system performs preliminary measurement of substrate permittivity and absorption coefficients before the actual object detection measurement. This preliminary characterization allows the system to adaptively adjust measurement parameters and compensate for frequency-dependent attenuation, enabling accurate deep measurements even at higher frequencies where attenuation would normally limit penetration depth.
Solution Approach 2:
The system changes the operating frequency dynamically based on the measured substrate properties. By measuring permittivity and absorption at the actual operating frequency rather than using fixed reference values, the system can optimize the frequency selection to achieve both sufficient penetration depth and required depth resolution for the specific substrate conditions.
2Reliability
If high power is introduced into the substrate to compensate for high absorption, then signal-noise ratio is improved, but energy consumption increases and deep-lying object detection becomes less efficient
Solution Approach 1:
The system uses feedback from the measured substrate permittivity and absorption coefficients to adaptively control the transmitted power level. By continuously monitoring substrate properties and adjusting power accordingly, the system maintains optimal signal-noise ratio for detecting deep-lying objects while minimizing unnecessary energy consumption that would occur with fixed high-power operation.
3Measurement precision
If permittivity is measured at high frequency to match measurement frequency, then frequency accuracy is improved, but object signal interference increases and measurement accuracy decreases
Solution Approach 1:
The system performs permittivity measurement as a preliminary step before object detection. By measuring substrate properties first when no object is present or before the object influences the field, the system obtains accurate baseline permittivity values without contamination from object signals. This preliminary characterization is then used to interpret subsequent object detection measurements.
Solution Approach 2:
The system periodically updates permittivity measurements at the actual operating frequency during the measurement process, especially when transitioning between different substrates or depth ranges. This periodic recalibration ensures that the most current substrate properties are used for interpretation while minimizing the time objects are present in the measurement field, thereby reducing interference.
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 system effectively suppresses the influence of embedded objects on permittivity measurement, enabling accurate depth determination and optimizing power usage by adjusting the alternating electric field strength based on extrapolated absorption, thus improving measurement depth and resolution.
Implementation Method 1
high-frequency alternating electric fields are introduced by a detection antenna into the substrate to be examined. The interaction of these high-frequency alternating electric fields with the objects is fed back with a delay to the detection antenna.
Implementation Method 2
a permittivity measurement device with at least one auxiliary potential plate for measuring a permittivity measurement signal of the substrate at a permittivity measurement frequency that is lower than the measurement frequency
Implementation Method 3
The propagation velocity υ of the electromagnetic interaction in media is reduced relative to that of the speed of light in vacuum c0 by the divisor √{square root over (∈r)}, where ∈r is the relative permittivity of the medium.
Implementation Method 4
The salts are usually dissolved in interstitial water which leads to conductivity σ and, therefore, resistive losses, so that the absorption α by the substrate of the introduced electromagnetic interaction depends upon the penetration depth.
Data Source
AI summary
A wall detector (1) for detecting an object (3) embedded in a substrate (2) includes a detection antenna (5) for introducing broadband, high-frequency alternating electric fields (9) of a measurement frequency (fM) in the substrate (2); a measurement system (6) connected to the detection antenna (5) for measuring the delayed interaction of the alternating fields (9) with the object (3), a calculation device (7) for detecting the object (3) based on the measurement signal and for determining the associated depth information, and a permittivity measurement device (8) with at least one auxiliary potential plate (11) for measuring the permittivity measurement signal of the substrate at a permittivity measurement frequency (fp) that is a lower than the measurement frequency; and an associated measurement method.