Radar Noise Measurement via Waveguide Loopback
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Solution Overview
Problem
Radar systems face challenges in accurately measuring amplitude noise and uncorrelated phase noise, which degrade the noise floor and impact the detection of objects, especially in the presence of strong reflectors, due to finite transmission/reception isolation and flicker upconversion.
Innovation Solution
An FMCW radar system with a waveguide loopback and variable phase shifter is used to measure amplitude noise and uncorrelated phase noise by generating and processing baseband I and Q signals, allowing for the separation and quantification of noise components without external equipment, utilizing a power amplifier, low noise amplifier, and IQ generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional noise measurement methods are used in radar systems, then the measurement process requires external equipment and complex setup, but the measurement precision is insufficient to accurately separate amplitude noise and uncorrelated phase noise
Solution Approach 1:
The radar system measures its own noise characteristics by utilizing its internal components (transmitter, receiver, waveguide loopback) without requiring external measurement equipment. The system loops back its transmitted signal through a waveguide and processes it through the receiver chain, enabling self-diagnosis and noise characterization.
Solution Approach 2:
The invention extracts and separates the uncorrelated phase noise and amplitude noise components from the total noise signal by using a variable phase shifter to create phase differences between signal paths, allowing independent measurement of each noise component through mathematical processing of the I and Q channel outputs.
2Reliability
If the radar system uses finite transmission/reception isolation, then the system structure is simpler, but the noise floor degrades and detection accuracy of small objects decreases
Solution Approach 1:
The invention converts the harmful leakage signal (due to finite isolation) into a useful measurement tool by deliberately looping back the transmitted signal through the waveguide and receiver chain. This allows the system to characterize and quantify its own noise properties, including the impact of isolation limitations, and compensate for these effects in the detection algorithm.
3Adaptability or versatility
If the radar system measures noise in the presence of strong reflectors, then the measurement can be performed in realistic operating conditions, but the detection of small objects is masked by the noise from large objects
Solution Approach 1:
The invention segments the total received signal into I (in-phase) and Q (quadrature) components using a 90-degree hybrid coupler, and further segments the noise analysis by creating separate measurement paths with different phase shifts. This allows independent analysis of noise components even when strong reflectors are present, as the phase diversity enables separation of target signal from noise floor.
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 method enables accurate measurement of amplitude noise and uncorrelated phase noise within the radar system, improving the noise floor and enhancing the detection range and accuracy of small objects in the presence of larger objects, reducing the impact of noise on radar performance.
Implementation Method 1
a power amplifier (PA) for amplifying a local oscillator (LO) signal, to generate an amplified signal
Implementation Method 2
a waveguide loopback for guiding the amplified signal from the transmitter to the receiver as the looped back signal
Implementation Method 3
a low noise amplifier (LNA) for amplifying a looped back signal, to generate a receiver signal
Implementation Method 4
an IQ generator for generating an I signal based on the LO signal and for generating a Q signal based on the LO signal
Implementation Method 5
a first mixer for mixing the receiver signal and the I signal, to generate a baseband I signal
Implementation Method 6
a second mixer for mixing the receiver signal and the Q signal, to generate a baseband Q signal
Data Source
AI summary
A radar system includes a transmitter including a power amplifier (PA) for amplifying a local oscillator (LO) signal, to generate an amplified signal. The radar system also includes a receiver including an IQ generator for generating an I signal based on the LO signal and for generating a Q signal based on the LO signal and a low noise amplifier (LNA) for amplifying a looped back signal, to generate a receiver signal. The receiver also includes a first mixer for mixing the receiver signal and the I signal, to generate a baseband I signal and a second mixer for mixing the receiver signal and the Q signal, to generate a baseband Q signal. Additionally, the radar system includes a waveguide loopback for guiding the amplified signal from the transmitter to the receiver as the looped back signal.