MIMO Antenna Array Layout for Wide-Angle Fill-Level Profiling
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Solution Overview
Problem
Existing fill-level measuring devices struggle to provide a high angular separation of fill-level profiles over a large solid-angle range, especially with limited evaluation channels, particularly when dealing with inhomogeneous solid-like filling materials.
Innovation Solution
An antenna assembly comprising a main antenna array with transmitting and receiving antennas spaced greater than half the wavelength, combined with a sub-antenna array, allows for high angular separation and unambiguous assignment of solid angles, using the MIMO principle to create a conjugated solid-angle spectrum for accurate fill-level profiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If antennas are arranged at a separating distance greater than half the wavelength to achieve high angular separation, then angular separation is improved, but the number of required antennas and evaluation channels increases
Solution Approach 1:
The antenna assembly is divided into a main antenna array and a sub-antenna array. The main antenna array uses antennas spaced at more than half the wavelength to achieve high angular separation, while the sub-antenna array with fewer elements fills in the angular gaps. This segmentation allows the system to achieve complete angular coverage with fewer total antennas than would be required if all antennas were spaced at greater than half-wavelength intervals throughout.
Solution Approach 2:
The patent transitions from a one-dimensional linear arrangement of antennas to a two-dimensional grid arrangement by introducing the sub-antenna array at different spatial positions. This dimensional expansion allows the system to achieve complete angular coverage through the combined effect of multiple arrays with different geometries, reducing the total number of elements needed compared to a single dense array.
2Measurement precision
If antennas are arranged at a separating distance greater than half the wavelength, then angular separation is improved, but unambiguous assignment of solid angles becomes difficult
Solution Approach 1:
The measurement function is segmented between the main antenna array and sub-antenna array. The main array provides high angular separation for most directions, while the sub-array specifically targets and fills the angular gaps where unambiguous assignment would otherwise be lost. This functional segmentation restores complete unambiguous coverage.
Solution Approach 2:
The sub-antenna array acts as an intermediary that mediates the angular coverage gaps created by the main antenna array's sparse spacing. By adding this intermediate structure, the system recovers the lost angular information without requiring the main array to be densely populated, thus maintaining low complexity while achieving complete unambiguous coverage.
3Measurement precision
If a large solid-angle range is covered with high angular separation, then measurement accuracy is improved, but the number of evaluation channels required increases
Solution Approach 1:
The evaluation task is segmented into two stages: first, the main antenna array processes signals to achieve high angular separation for the majority of the solid-angle range; second, the sub-antenna array processes signals to fill the remaining angular gaps. This segmentation allows the total number of evaluation channels to be much lower than what would be required for a single comprehensive high-resolution array.
Solution Approach 2:
Instead of designing a single antenna array that provides complete high-resolution coverage across the entire solid-angle range (which would require many channels), the patent uses partial action by having the main array cover most angles at high resolution and the sub-array cover only the remaining gaps. This partial coverage approach for each array results in excessive total coverage when combined, achieving the goal with fewer total channels.
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 the determination of a fill-level profile with high angular separation and accuracy over a wide solid-angle range using a reduced number of antennas and evaluation channels, effectively addressing the limitations of prior art devices.
Implementation Method 1
Radar-based measuring methods are therefore predominantly used in the field of continuous fill-level measurement
Implementation Method 2
the radar signal reflected by the filling material surface
Data Source
AI summary
A radar-based fill-level measuring device for determining a three-dimensional fill-level profile by the MIMO principle comprises an antenna assembly which comprises a sub-antenna array in addition to a main antenna array. Angle-separating solid-angle spectra can be created by means of the main antenna array, and these solid-angle spectra are combined with those of the sub-antenna array. Accordingly, the sub-antenna array is designed such that its solid-angle spectra permit a unique assignment of each solid angle in the entire solid-angle range. For this purpose, the corresponding antennas are arranged on an intermediate grid. The advantage of this is that with a total of very few antennas or a fast evaluation associated therewith over a wide solid-angle range a highly angle-separating fill-level profile can be captured.