PLL Radar Level Gauge Without Frequency Multiplier Phase Noise
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Solution Overview
Problem
Radar fill level measuring devices often require complex electronic circuits and frequency multipliers, leading to increased power consumption, size, and phase noise, which complicates their design and reduces reliability.
Innovation Solution
A radar fill level measuring device with a phase-locked loop that omits the frequency multiplier, using a fundamental wave oscillator or push-push oscillator directly coupled to a transmit/receive filter, reducing circuit complexity and power consumption while improving phase noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a frequency multiplier is used to generate high-frequency radar signals, then the transmission frequency can be increased, but the device complexity, power consumption, and phase noise increase
Solution Approach 1:
The patent removes the frequency multiplier component from the radar signal generation system. Instead of using a frequency multiplier to generate high-frequency signals, the system directly uses a voltage-controlled oscillator (VCO) operating at the desired high frequency (e.g., 60 GHz or higher), thereby eliminating the complex frequency multiplication stage and its associated power consumption and phase noise issues
Solution Approach 2:
The patent changes the operating parameters of the oscillator to directly generate high-frequency radar signals without frequency multiplication. The VCO is designed to operate directly at the target frequency range (60 GHz and above), changing the frequency generation approach from multiplication to direct oscillation, which simplifies the circuit and reduces power consumption
2Power
If a frequency multiplier is used to generate high-frequency radar signals, then the transmission frequency can be increased, but phase noise increases
Solution Approach 1:
The patent removes the frequency multiplier component that causes phase noise multiplication. By using a VCO that directly generates the high-frequency radar signal without frequency multiplication, the system eliminates the phase noise amplification that occurs in frequency multipliers, thereby improving phase noise performance and signal quality
Solution Approach 2:
The patent replaces the complex frequency multiplier chain with a simpler, more direct VCO-based frequency generation approach. This substitution uses a single oscillator component instead of multiple frequency multiplication stages, reducing cumulative phase noise and improving overall signal quality
3Power
If complex electronic circuits are used to implement radar fill level measuring devices, then the transmission signal can be generated, but the device size and complexity increase
Solution Approach 1:
The patent combines the frequency generation function into a single VCO component that directly produces the high-frequency radar signal. This merging of functions eliminates the need for separate frequency multiplier circuits, phase detectors, and associated control circuits, thereby simplifying the overall electronic circuit architecture while maintaining transmission signal generation capability
Solution Approach 2:
The VCO serves multiple functions simultaneously: it generates the base frequency, provides the high-frequency radar signal directly, and eliminates the need for separate frequency multiplication circuits. This multi-functional approach reduces the overall circuit complexity and component count while maintaining full radar signal generation capability
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
The solution results in a more robust, reliable, and compact radar fill level measuring device with reduced power consumption and phase noise, maintaining functionality while simplifying the design.
Implementation Method 1
The radar module has a phase locked loop. The phase-locked loop in turn has an oscillator for outputting an output signal at an output of the oscillator, a phase detector coupled to the output of the oscillator, and a frequency divider coupled between the output of the oscillator and an input of the phase detector for generating a frequency-divided signal based on the output signal of the oscillator
Implementation Method 2
The phase detector also has a reference input for receiving a reference frequency signal and a phase detector output which is coupled to a control input of the oscillator. The phase detector is designed to determine and/or determine a phase difference between the reference frequency signal and the frequency-divided signal generated based on the output signal of the oscillator, which can be provided by the frequency divider, and to output a control signal correlating with the determined phase difference
Implementation Method 3
Furthermore, the radar module has a transmit/receive filter coupled between the oscillator and the antenna for separating the transmitted signal and the received signal
Implementation Method 4
The radar fill level measuring device also has at least one antenna coupled to the radar module, such as a horn antenna and/or a parabolic antenna, for emitting the transmission signal to a surface of a medium and for receiving a reception signal reflected on the surface
Implementation Method 5
The radar module has a phase locked loop. The phase-locked loop in turn has an oscillator for outputting an output signal at an output of the oscillator
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A radar level gauge (10) for determining the fill level of a medium is proposed, comprising a radar module (12) for generating a transmit signal (11) with a transmission frequency of at least 60 GHz and at least one antenna (14) for transmitting the transmit signal (11) and for receiving a received signal (13) reflected from the medium. The radar module (12) includes a phase-locked loop (16) comprising an oscillator (18) for outputting a signal at an output (19, 21), a phase detector (20), and a frequency divider (26) coupled between the output (19, 21) of the oscillator (18) and an input (23) of the phase detector (20) for generating a frequency-divided signal.The radar module further comprises a transmit-receive switch (40) coupled between the oscillator (18) and the antenna (14), which is coupled to the same output (19, 21) of the oscillator (18) as the frequency divider (26), wherein the output (19, 21) of the oscillator (18) is directly connected to an input (41) of the transmit-receive switch (40), and wherein the phase detector (20) has a reference input (27) for receiving a reference frequency signal and a phase detector output (25) which is coupled to a control input (17) of the oscillator (18). The phase detector (20) is designed to determine a phase difference between the reference frequency signal and the frequency-split signal and to output a control signal correlated with the determined phase difference at the phase detector output (25) to control the output frequency of the output signal of the oscillator (18) to the control input (17) of the oscillator (18).