DDM MIMO Radar Phase Control via Signal Path Lengths

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Solution Overview

Problem

Existing Doppler Division Multiplexing (DDM) MIMO radar systems require multiple transmitter channels, leading to increased area, power consumption, and cost, as well as difficulties in accurately controlling phase shifts using digital techniques.

Innovation Solution

A DDM MIMO radar system design that uses a single transmitter connected to multiple antennas via signal paths of different electrical lengths, generating phase differences between chirps and antennas to achieve orthogonality, allowing for precise phase shift control and reduced system complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple transmitter channels are used to achieve high angular resolution in DDM MIMO radar, then angular resolution is improved, but area, power consumption, and system complexity increase

Engineering Contradiction:
Improveangular resolutionVSAvoidnumber of transmitter channels
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple transmitter channels into a single transmitter by using multiple antennas with different electrical lengths. The single transmitter generates chirps that are distributed across multiple Doppler bands through the differential electrical lengths, eliminating the need for multiple separate transmitters while maintaining the angular resolution performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single transmitter performs multiple functions by generating signals for multiple virtual channels simultaneously. The transmitter is configured to generate M chirps in a radar cycle frame that are distributed across N virtual channels through the different electrical lengths of the signal paths, making one transmitter serve multiple purposes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If digital phase shift control is used in conventional DDM MIMO radar, then phase control is achieved, but accuracy deteriorates due to large error values

Engineering Contradiction:
Improvephase control capabilityVSAvoidphase shift accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces digital phase shift control with an analog approach using different electrical lengths of signal paths. Instead of using digital phase shifters that introduce quantization errors, the system uses physical length differences in the signal paths to create precise phase shifts, achieving higher accuracy without digital control limitations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If multiple transmitter channels are implemented, then orthogonal signal generation is achieved, but energy consumption and power dissipation increase

Engineering Contradiction:
Improvesignal orthogonalityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent merges multiple transmitter channels into a single transmitter that generates orthogonal signals through different electrical lengths. This consolidation reduces the number of active transmitter components, thereby reducing overall energy consumption and power dissipation while maintaining signal orthogonality through the differential path lengths.

Inventive Principle:
Principle #5Merging (Combining)

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 approach reduces energy consumption, power dissipation, and chip area while maintaining performance by using waveguides with varying lengths to set precise phase shifts, improving the system's angular resolution and efficiency.

Implementation Method 1

a phase of a signal transmitted by the transmitter is different at each of the plurality of transmitter antennas

Methodology Applied
Scientific EffectPhase difference generation through electrical length variation:

Implementation Method 2

Each channel can be identified at the receiver because it will fall in a different band frequency in the doppler spectrum

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP3929622B1Radar system
Publication Date: 2024.08.07 NXP USA INC
  • EP3929622B1 patent drawingFigure 1~2
  • EP3929622B1 patent drawingFigure 3~4
  • EP3929622B1 patent drawingFigure 5~6

AI summary

The disclosure relates to a doppler division multiplexing MIMO radar system. Example embodiments include a doppler division multiplexing, DDM, multiple input multiple output, MIMO, radar system (400) comprising: a transmitter (401) connected to a plurality of transmitter antennas (4021-N) via a corresponding plurality of signal paths (4031-N) of different electrical lengths (L1-N) such that a phase of a signal transmitted by the transmitter (401) is different at each of the plurality of transmitter antennas (4021-N).