Asymmetric Radar Antenna Beam Symmetry

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Solution Overview

Problem

Radar devices experience performance deterioration due to angle misalignment of antennas, which narrows the detection range of objects, caused by mounting variations and changes in vehicle posture during travel.

Innovation Solution

The radar device employs plural unit antennas with asymmetrically arranged antenna elements relative to a virtual straight line passing through the antenna phase center, where one unit antenna is configured as a transmitting antenna and the other as a receiving antenna, or vice versa, to maintain bilateral symmetry and compensate for asymmetry when the elevation angle is misaligned.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If antenna elements are asymmetrically arranged with respect to a vertical line passing through antenna phase center, then the beam pattern can be designed for a predetermined elevation angle, but when the elevation angle is misaligned, the beam pattern tilts leftward or rightward causing bilateral symmetry loss and detection range narrowing

Engineering Contradiction:

Improvebeam pattern symmetryVSAvoiddetection range

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies asymmetry by intentionally designing the antenna element arrangement to be asymmetric with respect to the vertical line passing through the antenna phase center. This asymmetric configuration, when combined with the specific phase difference between antenna elements, enables the beam pattern to maintain bilateral symmetry even when the elevation angle is misaligned, thereby preventing beam pattern tilt and maintaining detection range.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the parameters of the antenna system by introducing a specific phase difference between the antenna elements in addition to the asymmetric spatial arrangement. This parameter change allows the system to compensate for elevation angle misalignment and maintain beam pattern symmetry across varying conditions.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the radar device is mounted on a vehicle, then it can be used for practical applications, but mounting variation and vehicle posture changes cause elevation angle misalignment from the predetermined angle

Engineering Contradiction:

Improvemounting flexibilityVSAvoidelevation angle alignment

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The asymmetric arrangement of antenna elements provides inherent compensation for elevation angle variations caused by mounting differences and vehicle posture changes. This design allows the radar to maintain accurate beam patterns without requiring precise elevation angle alignment during installation.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The antenna configuration serves multiple functions: it maintains beam pattern symmetry at the predetermined elevation angle while simultaneously compensating for elevation angle misalignment. This universal design enables the radar to operate effectively across various mounting conditions and vehicle postures without requiring adjustment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If symmetric antenna arrangement is used, then bilateral symmetry is maintained, but when elevation angle is misaligned, the beam pattern tilts causing performance deterioration

Engineering Contradiction:

Improvebeam pattern symmetryVSAvoiddetection performance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent counterintuitively uses asymmetry in the antenna element arrangement to achieve symmetry in the beam pattern under misaligned conditions. The asymmetric spatial configuration, combined with appropriate phase differences, creates a beam pattern that maintains bilateral symmetry even when the elevation angle deviates from the predetermined angle, thereby preventing performance deterioration.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The asymmetric antenna arrangement acts as a preliminary compensatory measure that anticipates and counteracts the beam pattern tilt that would otherwise occur due to elevation angle misalignment. By pre-configuring the asymmetric arrangement, the system proactively prevents the harmful effect of beam tilt before it occurs.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS11474196B2Radar device

Publication Date: 2022.10.18 DENSO TEN LTD

AI summary

A radar device includes: plural unit antennas, each including plural antenna elements configured to transmit or receive a radio wave, the plural antenna elements being aligned in a predetermined direction in a plane and connected by a transmission line. The plural unit antennas include a first unit antenna having plural antenna elements arranged asymmetrically with respect to a virtual straight line parallel to the predetermined direction, the virtual straight line passing through an antenna phase center of the first unit antenna, and a second unit antenna having plural antenna elements arranged asymmetrically with respect to a virtual straight line parallel to the predetermined direction passing through an antenna phase center of the second unit antenna. The plural antenna elements of the second unit antenna are arranged in a manner substantially symmetrical to the plural antenna elements of the first unit antenna with respect to the virtual straight line.