Pulse Radar Fill Level Measurement with Frequency-Varying Antenna
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Solution Overview
Problem
Conventional pulse radar fill level measuring devices are not optimally suited for measuring bulk materials, as they fail to accurately record the surface profile of mountainous or valley-shaped material cones, and are prone to interference from lateral protrusions, requiring complex and maintenance-intensive systems or multiple antennas.
Innovation Solution
A pulse radar fill level measuring device with a waveguide slot antenna that transmits microwave pulses with varying center frequencies, utilizing different spatial radiation characteristics to distinguish between reflections from the material surface and interferers, allowing for reliable measurement in a wide range of applications with a single, mechanically robust antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pulse radar fill level measuring devices are used, then the measurement principle is simple and reliable, but the device cannot accurately measure bulk materials with mountainous or valley-shaped surface profiles
Solution Approach 1:
The patent changes the parameter of center frequency by transmitting microwave pulses with at least two different center frequencies instead of a fixed frequency. This allows the radiation characteristics to vary with frequency, enabling the beam to better interact with bulk material surfaces and distinguish between material surface reflections and interferer reflections, thereby achieving accurate measurements for bulk materials while maintaining the simplicity of the pulse radar principle.
2Measurement precision
If imaging radar systems with multiple antennas are used, then surface profile recording is achieved, but the device complexity and maintenance requirements increase significantly
Solution Approach 1:
The patent makes a single antenna universal by enabling it to transmit at multiple different center frequencies, each producing different radiation characteristics. This single antenna performs the function that would otherwise require multiple antennas, achieving surface profile recording capability while avoiding the complexity of multiple antennas and their associated control systems.
Solution Approach 2:
The patent uses parameter changes (center frequency variation) to achieve different radiation patterns from a single antenna, replacing the need for multiple physically different antennas. This allows surface profile recording through frequency-based beam characterization rather than spatial antenna arrays.
3Measurement precision
If mechanically pivotable antennas are used, then surface profiles can be recorded, but the device becomes more complex and requires intensive maintenance
Solution Approach 1:
The patent replaces the mechanical pivotable antenna system with an electronically controlled frequency variation system. Instead of mechanically moving the antenna to change beam direction and record surfaces, the system uses electronic frequency modulation to achieve different radiation characteristics, eliminating mechanical complexity and maintenance requirements while maintaining measurement capability.
4Measurement precision
If multiple independently operated fill level measuring devices are used, then surface profiles can be derived, but the installation space and system complexity increase
Solution Approach 1:
The patent merges the functionality of multiple independently operated fill level measuring devices into a single device that transmits at multiple frequencies. This consolidation achieves surface profile derivation capability while reducing installation space requirements, as one multi-frequency antenna system replaces what would otherwise require multiple single-frequency devices positioned at different locations.
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 accurate measurement of fill levels in bulk materials and applications with lateral interferers, reducing complexity and maintenance needs while requiring minimal space and a single antenna installation.
Implementation Method 1
a pulse radar fill level measuring device for contactlessly measuring the fill level
Implementation Method 2
receives the signal components reflected back in the container in the direction of the antenna
Implementation Method 3
which depends on the center frequency of the transmission signals and has different spatial radiation characteristics for different center frequencies
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
Disclosed is a fill level measurement device (5, 25), which works according to the pulse radar principle, for measuring a fill level (L) of a filling material (3, 21, 32) in a container (1), comprising a transmission device (11) with a pulse generation device (15) which is connected to a control unit (13) and which, for each measurement, generates a transmission signal (Sn) consisting of at least one microwave pulse, in particular of a sequence of periodically mutually succeeding microwave pulses of a predetermined average frequency (fn), for the respective measurement according to predetermined measurement cycles that each comprise at least two measurements, the average frequencies (fn) of the transmission signals (Sn) of at least two of the measurements differing from each other; further comprising an antenna (9, 27), which is connected to the transmission device (11), receives the transmission signals (Sn) sent into the container (1) and the signal components thereof that are reflected in the container back towards the antenna (9, 27) as receiver signals (Rn), and has a different spatial emission characteristic that is dependent on the average frequency (fn) of the transmission signals (Sn) for different average frequencies (fn); further comprising a signal processing device (19), which is connected to the transmission device (11) and the antenna (9, 27) and which receives and evaluates the receiver signals (Rn) on the basis of the average frequencies (fn) of the microwave pulses of the corresponding transmission signals (Sn) and of the average frequency dependency of the spatial emission characteristic of the antenna (9, 27).