Microwave Soil Moisture Measurement via Signal Attenuation
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Solution Overview
Problem
Existing methods for measuring soil moisture are complex and costly, making large-scale regionalization of soil moisture measurements impractical due to the need for high-precision hardware and software systems.
Innovation Solution
A method using a microwave transmitter and receiver system between 300 MHz and 300 GHz, where the transmitter emits a defined signal and the receiver, located above the ground, determines soil moisture based on signal attenuation, utilizing empirical reference values for the dielectric constant and soil moisture relationship, with the frequency in the license-free ISM band and encoded transmission parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-precision measurement methods (TDR, FDR) are used to measure soil moisture, then measurement precision is improved, but device complexity and production costs increase significantly
Solution Approach 1:
The patent replaces complex electronic measurement systems (TDR, FDR) with a simplified optical/microwave-based system. Instead of using precision electronics to measure dielectric properties, the invention uses a microwave transmitter and receiver that measure signal attenuation, which correlates with soil moisture. This substitution of measurement methodology dramatically reduces hardware and software complexity while maintaining measurement capability.
Solution Approach 2:
The invention changes the measurement parameter from direct dielectric constant measurement to microwave signal attenuation measurement. By measuring how much the microwave signal is attenuated as it passes through the ground, the system infers soil moisture content. This parameter change simplifies the measurement process and reduces the complexity of required electronics.
2Measurement precision
If high-precision measurement systems are deployed for regional soil moisture monitoring, then measurement precision is improved, but production costs and device prices increase
Solution Approach 1:
The patent employs inexpensive microwave transmitters and receivers that can be manufactured at low cost using standard components. The system uses off-the-shelf microwave modules, simple antennas, and basic signal processing, eliminating the need for expensive precision electronics. This makes the devices affordable for large-scale deployment across regions.
Solution Approach 2:
By replacing expensive precision electronic measurement systems with simpler microwave-based attenuation measurement, the invention dramatically reduces production costs. The microwave system uses basic transmitters and receivers rather than complex TDR or FDR electronics, making manufacturing more accessible and devices more affordable.
3Measurement precision
If complex measurement systems are used for soil moisture monitoring, then measurement precision is improved, but ease of deployment for large-scale regionalization deteriorates
Solution Approach 1:
The patent divides the regional soil moisture monitoring task into many simple, independent measurement units. Each unit consists of a transmitter and receiver pair that can be deployed individually. This segmentation allows for scalable deployment from single points to entire regions, with each unit being simple enough for easy installation and operation.
Solution Approach 2:
The replacement of complex electronic systems with simple microwave transmitters and receivers makes deployment much easier. The simplified hardware requires less calibration, fewer specialized components, and less technical expertise for installation, enabling rapid deployment across large regions.
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 simplifies and robustly measures soil moisture, reducing costs and complexity, allowing for easier deployment of soil moisture sensors across regions.
Implementation Method 1
microwaves have the ability to penetrate media depending on their dielectric constant
Implementation Method 2
As the dielectric constant increases, the signal is increasingly attenuated. The absolute attenuation of the signal depends primarily on the dielectric constant of the ground and the distance traveled through the ground
Data Source
Figure 1
AI summary
The invention relates to a method for measuring soil moisture using at least one transmitter (1) and one receiver (3) in the microwave range between 300 MHz and 300 GHz, and an evaluation unit (4), comprising the following process steps: a) emitting a defined transmission power by the at least one transmitter (1) installed in the soil (2), b) receiving a reception power at the at least one receiver (3), and c) determining a soil moisture in the evaluation unit (4) taking into account the installation depth (T) of the transmitter (1), the height (H) of the receiver (3) above the soil (2), the transmission and reception power of the frequency, and a reference value of the soil (2), as well as a transmitter (1) and a receiver (3).