Radar Level Gauge Signal Isolation via Frequency Conversion
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Solution Overview
Problem
Current radar level gauge systems often exhibit insufficient sensitivity, particularly in applications with products that yield weak echo signals or operate in open or semi-open environments, where high sensitivity is required for reliable filling level determination.
Innovation Solution
The radar level gauge system incorporates a transceiver with first and second frequency converters to reduce signal leakage, achieving at least 30 dB signal isolation between the transmitter and receiver branches, thereby increasing sensitivity and allowing further enhancements such as noise reduction and signal amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal isolation between transmitter and receiver branches is increased (e.g., using separate antennas or directional couplers), then sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent divides the transceiver into separate transmitter and receiver branches with physically separated antennas. The transmitting antenna and receiving antenna are positioned to provide spatial isolation, reducing signal leakage from the transmitter to the receiver. This segmentation allows independent optimization of each branch for its specific function while achieving the required 30 dB signal isolation.
Solution Approach 2:
The patent introduces directional couplers as intermediary components between the signal generator and antennas. These couplers act as mediators that selectively transmit signals in desired directions while isolating opposing directions. The directional couplers provide the necessary signal isolation without requiring complete physical separation of all components, thus reducing overall system complexity while maintaining high sensitivity.
2Measurement precision
If frequency converters are added to reduce signal leakage, then sensitivity is improved, but device complexity increases
Solution Approach 1:
Frequency converters are introduced as intermediary components in the signal path. These converters transform the transmitted frequency to a different frequency, creating a frequency domain separation between transmitted and received signals. This allows the receiver to selectively process only the reflected signals at the converted frequency while rejecting the original transmitted frequency, thereby reducing signal leakage effects and improving sensitivity despite the added complexity.
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 configuration significantly enhances the measurement sensitivity of the radar level gauge system, allowing for reliable filling level determination even in challenging applications, with the potential for noise-limited performance when signal isolation reaches 50 dB.
Implementation Method 1
a transceiver for generating, transmitting and receiving frequency-modulated electromagnetic signals
Implementation Method 2
signals are reflected. The reflected signals are received by the radar level gauge system
Implementation Method 3
a first frequency converter for converting the frequency of the frequency-modulated signal to provide the transmitted electromagnetic signal
Implementation Method 4
a second frequency converter for converting the frequency of the frequency-modulated signal
Implementation Method 5
a mixer having a first input connected to the signal generator via a second frequency converter for converting the frequency of the frequency-modulated signal and a second input connected to the receiver branch, for forming an intermediate frequency signal indicative of a phase difference
Data Source
AI summary
A radar level gauge system for determining a filling level of a product contained in a tank, comprising: a transceiver for generating, transmitting and receiving frequency-modulated electromagnetic signals; a transmitting propagating device electrically connected to the transceiver and arranged to propagate transmitted electromagnetic signals towards a surface of the product contained in the tank; and a receiving propagating device electrically connected to the transceiver and arranged to return echo signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signals, including a surface echo signal resulting from reflection at the surface, back to the transceiver.