Microwave Moisture Density Measurement via Time Domain Pulse Analysis
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Solution Overview
Problem
Existing methods for measuring moisture and density in materials using microwave technology face limitations, particularly in non-contact measurements for large objects, as they are density-dependent and require contact with the material, failing to accurately assess core moisture and density in extended objects like large bales or boxes.
Innovation Solution
A method and device utilizing a microwave transmitter and receiver with an evaluation unit to determine the complex-valued transfer function of the material, transforming it into the time domain to isolate the main pulse, allowing for density-independent moisture and moisture-independent density measurements by analyzing parameters A, B, and H, which are independent of the material's thickness and precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resonator methods are used to measure moisture and density, then measurement precision is improved, but the method is fundamentally limited to surface measurements only and cannot measure core moisture in large materials
Solution Approach 1:
The patent replaces contact-based resonator methods with non-contact microwave transmission measurement. Electromagnetic waves are transmitted through the material from one side to the other, allowing penetration into the core of large materials. The transmission characteristics (amplitude attenuation and phase shift) are measured to determine moisture content and density, eliminating the surface-only limitation of resonator methods while maintaining measurement precision.
2Measurement precision
If contact measurement methods are used, then measurement precision is improved, but the device must be placed in immediate vicinity or contact with the material, reducing ease of operation
Solution Approach 1:
The patent replaces mechanical contact measurement systems with non-contact electromagnetic wave transmission. The microwave transmitter and receiver can be positioned at a distance from the material, eliminating the need for immediate vicinity placement or physical contact. This maintains measurement precision through electromagnetic interaction while significantly improving ease of operation for large or difficult-to-access materials.
3Volume of moving object
If traditional transmission measurement is used, then core moisture measurement is enabled, but the measurement is density-dependent and cannot provide density-independent moisture values
Solution Approach 1:
The patent employs a dual-parameter measurement approach where both amplitude attenuation and phase shift are measured simultaneously. These two parameters provide independent equations that can be solved together to determine both moisture content and density separately. This feedback mechanism allows the system to decouple the density-dependent effects from the moisture measurement, providing density-independent moisture values while maintaining core measurement capability.
Solution Approach 2:
The patent changes the measurement parameters from single-frequency or single-parameter measurements to multi-frequency or dual-parameter measurements. By measuring both amplitude and phase characteristics, or by using multiple frequencies, the system obtains sufficient independent information to separate the effects of moisture and density, enabling accurate moisture measurement independent of density variations.
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
Enables precise, non-contact measurement of moisture and density in materials, independent of density and thickness, with the main pulse's characteristics providing reliable parameters for accurate evaluation, and is suitable for various types of goods including large bales and boxes.
Implementation Method 1
The measurement is carried out on dielectric materials by transmission of electromagnetic radiation through the material to be measured
Implementation Method 2
Electromagnetic waves that interact with the material to be measured experience both attenuation and wavelength reduction in the material to be measured
Implementation Method 3
the dielectric properties of the moist material to be measured are largely determined by the dielectric properties of the water it contains
Implementation Method 4
The complex-valued transmission function of the measurement material is transformed into a complex-valued time domain function in the time domain
Data Source
AI summary
The invention relates to a method for humidity and/or density measurement in a sample material, using a microwave transmitter, a microwave receiver and an analytical unit which can determine the phase and amplitude of microwave radiation from the microwave transmitter received by the microwave receiver and n which a complex transmission function for the measuring arrangement can be stored. Said method comprises the following steps: the phase and amplitude are determined for a number of frequencies of the microwave radiation transmitted through the sample material, using the complex transmission function for the measuring arrangement the complex transmission function sample material is calculated from the determined values and transformed into the time domain as a complex time domain function, the maximum value of the main pulse is determined as parameter A from the time domain function, the width of the main pulse is calculated as parameter B from the time domain function and/or the amplitude value for the main pulse is determined as parameter H and a humidity and/or density of the sample material is determined based on the parameter A and the parameter B and/or H.