FMCW Generator Feedback Loop for High-Linearity Radar Chirps

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing FMCW radar systems face challenges in implementing high-speed broadband signal generators with improved frequency linearity, often resulting in complex structures and high power consumption.

Innovation Solution

A device comprising a ramp signal generator, a reference signal generator, a phase locked loop, and a voltage-controlled oscillator, which uses an analog ramp signal to generate a frequency-modulated continuous wave, incorporating a pulse generator, operational amplifier, and temperature-controlled crystal oscillator to enhance frequency linearity and reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing frequency synthesizers are used to generate broadband FMCW signals at high speed, then the frequency modulation width is increased, but the device complexity and power consumption increase

Engineering Contradiction:

Improvedistance resolutionVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex digital frequency synthesizers with an analog-based solution using a voltage-controlled oscillator (VCO) and ramp signal generator. This substitution of mechanical/electronic analog components for digital systems reduces device complexity while maintaining the ability to generate broadband FMCW signals with sufficient distance resolution for radar applications

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If existing frequency synthesizers are used to generate broadband FMCW signals at high speed, then the frequency modulation width is increased, but the power consumption increases

Engineering Contradiction:

Improvedistance resolutionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent substitutes power-intensive digital frequency synthesizers with lower-power analog components including a VCO and ramp signal generator. This replacement significantly reduces power consumption while preserving the frequency modulation width necessary for accurate distance measurement and target detection in radar systems

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the frequency linearity of the FMCW is improved using existing methods, then the radar performance is enhanced, but the device complexity increases

Engineering Contradiction:

Improvefrequency linearityVSAvoidcircuit complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where a portion of the VCO output is fed back to the ramp signal generator through a phase-frequency detector and charge pump. This feedback loop automatically corrects frequency linearity errors without requiring complex external calibration circuits, thereby improving frequency linearity while keeping the overall device complexity manageable

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces a ramp signal generator as an intermediary component between the voltage source and the VCO. This intermediary generates a controlled ramp voltage that linearly modulates the VCO frequency, simplifying the circuit architecture compared to direct digital synthesis methods while achieving superior frequency linearity

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enables the generation of high-speed FMCW signals with improved linearity, simplifying the circuit configuration and reducing power consumption while maintaining performance.

Implementation Method 1

a phase locked loop configured to output a control voltage based on the reference signal

Methodology Applied

Scientific EffectPhase difference detection:

Implementation Method 2

a voltage-controlled oscillator configured to generate a frequency-modulated continuous wave based on the control voltage

Methodology Applied

Scientific EffectVoltage-controlled frequency modulation:

Implementation Method 3

an operational amplifier configured to amplify a potential difference across the capacitor

Methodology Applied

Scientific EffectElectrical amplification:

Implementation Method 4

a temperature sensor configured to sense a temperature of the frequency-modulated continuous wave generator, wherein the reference signal generator may be configured to generate the reference signal by further considering a detection result of the temperature sensor

Methodology Applied

Scientific EffectTemperature sensing:

Data Source

PatentUS10976409B2Frequency-modulated continuous wave generator and frequency-modulated continuous wave radar system including the same

Publication Date: 2021.04.13 ELECTRONICS & TELECOMM RES INST

AI summary

Provided is frequency-modulated continuous wave generator. The frequency-modulated continuous wave generator includes a ramp signal generator configured to generate an analog ramp signal, a reference signal generator configured to generate a reference signal based on the analog ramp signal, a phase locked loop configured to output a control voltage based on the reference signal, and a voltage-controlled oscillator configured to generate a frequency-modulated continuous wave based on the control voltage. The ramp signal generator is further configured to generate the analog ramp signal based on a feedback signal based on the frequency-modulated continuous wave.