Cascaded FMCW Radar PLL Synchronization Without RF Distribution

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Solution Overview

Problem

Conventional cascaded FMCW radars face challenges in synchronizing high-frequency signal generators across multiple transceiver chips, leading to increased circuit complexity, size, and power consumption due to the need for transmission lines and power dividers, which also limits angle resolution.

Innovation Solution

A cascaded FMCW radar design that synchronizes all signal generators within transceiver chips using a single crystal oscillator and a trigger signal, eliminating the need for transmission lines and power dividers, and using low-frequency reference signals to facilitate circuit expansion and miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional cascaded FMCW radar uses high-frequency signal generators in multiple transceiver chips, then angle resolution is improved, but circuit complexity and size increase due to the need for transmission lines and power dividers

Engineering Contradiction:

Improveangle resolutionVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the reference signal generation function into each transceiver chip by integrating a low-frequency signal generator (e.g., 77 MHz) directly within the chip. This eliminates the need for external transmission lines and power dividers, as each chip independently generates its own reference signal. The merging of functions within the chip reduces circuit complexity while maintaining the capability for high-angle-resolution measurements through multiple transceiver chips.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If a conventional cascaded FMCW radar uses high-frequency signal generators in multiple transceiver chips, then angle resolution is improved, but the area of the radar system increases due to transmission lines and power dividers

Engineering Contradiction:

Improveangle resolutionVSAvoidradar system area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If a conventional cascaded FMCW radar uses high-frequency signal generators in multiple transceiver chips, then angle resolution is improved, but power consumption increases

Engineering Contradiction:

Improveangle resolutionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the frequency parameter of the reference signal from high-frequency to low-frequency (e.g., 77 MHz). This parameter change allows for more efficient power management because low-frequency signals require less power to generate and maintain. The low-frequency reference signal is generated locally in each transceiver chip, eliminating the need for high-power amplifiers and complex power distribution networks, thereby reducing overall system power consumption while still enabling high-angle-resolution measurements.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If a conventional cascaded FMCW radar uses a master-slave configuration with high-frequency signals, then synchronization is achieved, but the circuit requires transmission lines and power dividers increasing complexity

Engineering Contradiction:

Improvesignal synchronizationVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the reference signal generation function by providing each transceiver chip with its own independent low-frequency signal generator (e.g., 77 MHz). This segmentation eliminates the need for a master-slave configuration where one chip generates high-frequency signals that must be distributed to others. Each chip operates independently with its own locally generated reference signal, achieving synchronization without requiring complex transmission lines and power dividers.

Inventive Principle:

Principle #1Segmentation

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 design enables easier circuit implementation and expansion, reduces power consumption, and maintains high angle resolution by synchronizing transceiver chips, thereby minimizing circuit size and cost.

Implementation Method 1

a crystal oscillator generating a reference frequency signal having low-frequency characteristics

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a signal generator provided therein transforming the reference frequency signal into an output signal having high-frequency characteristics

Methodology Applied

Scientific EffectPhase locked loop frequency synthesis:

Implementation Method 3

synchronizes all signal generators integrated in respective transceiver chips with one crystal oscillator

Methodology Applied

Scientific EffectPhase locking:

Data Source

PatentUS12498453B2Cascaded FMCW radar with synchronized PLL

Publication Date: 2025.12.16 CHUNG ANG UNIV IND ACADEMIC COOP FOUND

AI summary

Provided is a cascaded FMCW radar, and more particularly, to a cascaded FMCW radar with a synchronized PLL. The cascaded FMCW radar includes a crystal oscillator generating a reference frequency signal having low-frequency characteristics, a cascade-array transceiver chip generating an output signal having high-frequency characteristics using the reference frequency signal through a signal generator provided therein, and an antenna transmitting the generated output signal to the outside in the form of an electromagnetic wave or receiving the electromagnetic wave from the outside.