Array Antenna Air-Layer Structure for Wide-Angle Scan Stability

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Solution Overview

Problem

Array antenna devices face challenges in maintaining high gain and axial ratio when scanning in wide-angle directions due to amplitude differences between vertically and horizontally polarized waves, and surface waves on dielectric substrates, which are exacerbated by the difficulty in accurately adjusting substrate thickness, especially at high frequency bands like Ka or millimeter wave bands.

Innovation Solution

The use of conductive members that penetrate the dielectric substrate and function as spacers to create an air layer between the substrate and the conductor ground planes, allowing for precise adjustment of the air layer size to reduce amplitude differences and maintain high gain and axial ratio, with copper core balls providing accurate micrometer-scale adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a screw with narrow thread pitch is used to adjust substrate thickness, then adjustment accuracy is improved, but manufacturing difficulty increases significantly

Engineering Contradiction:
Improvesubstrate thickness adjustment accuracyVSAvoidscrew manufacturing difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces an intermediary adjustment mechanism consisting of a movable ground plane and adjustable spacers (rods or columns) that mediate between the substrate and the ground plane. This intermediary structure allows thickness adjustment without requiring precision-manufactured screws with micrometer-scale thread pitches, thereby resolving the contradiction between adjustment accuracy and manufacturing ease.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional screw-thread mechanical adjustment system with an alternative mechanical system using movable ground planes and spacers. This substitution eliminates the need for narrow thread pitch screws while achieving the same or better adjustment accuracy, particularly for micrometer-scale adjustments required in Ka-band and millimeter-wave applications.

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

2Ease of manufacture

If substrate thickness is not accurately adjusted, then manufacturing is easier, but gain and axial ratio performance deteriorates in wide-angle direction

Engineering Contradiction:
Improvesubstrate assembly easeVSAvoidantenna performance consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a dynamic adjustment mechanism where the ground plane can be moved relative to the substrate, and spacers can be adjusted to change the air layer thickness. This dynamic capability allows the antenna to be tuned for optimal performance in wide-angle directions while maintaining ease of manufacture, as the adjustment can be performed after assembly rather than requiring precise pre-manufacturing.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates preliminary adjustment features in the form of pre-positioned spacers and movable ground plane structures that facilitate subsequent thickness adjustment. This preliminary preparation enables easy post-assembly adjustment of the air layer thickness, ensuring both manufacturing ease and performance reliability without requiring complex precision manufacturing.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If conventional substrate adjustment methods are used, then device complexity is lower, but adjustment accuracy is insufficient for high frequency bands

Engineering Contradiction:
Improveadjustment mechanism complexityVSAvoidair layer thickness adjustment accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments the adjustment function into separate components: spacers (rods or columns) that define the air layer thickness and a movable ground plane that can be positioned relative to the substrate. This segmentation allows each component to be manufactured with standard precision while achieving micrometer-scale adjustment accuracy through their relative positioning, thereby reducing overall device complexity compared to precision-manufactured screws.

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

This configuration effectively suppresses gain and axial ratio decreases when scanning in wide-angle directions, even at high frequency bands, by allowing for precise adjustment of the air layer size, enhancing the antenna's performance and manufacturing feasibility.

Implementation Method 1

the remaining part of the plurality of conductive members functions as spacers for providing an air layer between the first dielectric substrate and the second conductor ground plane

Methodology Applied
Scientific EffectAir layer spacing:

Data Source

PatentEP3667821B1Array antenna device
Publication Date: 2023.11.29 MITSUBISHI ELECTRIC CORP
  • EP3667821B1 patent drawingFigure 1~2
  • EP3667821B1 patent drawingFigure 3~5
  • EP3667821B1 patent drawingFigure 6~8

AI summary

Included are: a first dielectric substrate (1) provided with a first conductor ground plane (2) on a front or back surface thereof; a plurality of patch antennas (3) formed in the first conductor ground plane (2), a plurality of conductive members (4), ends of which connected to the first conductor ground plane (2) so as to surround the patch antennas (3) individually, and a second conductor ground plane (5) connected to each of the other ends of the conductive members (4), in which in a case where the first conductor ground plane (2) is provided on the front surface of the first dielectric substrate (1), parts of the plurality of conductive members (4) penetrate the first dielectric substrate (1), and the remaining parts of the conductive members (4) function as spacers for providing an air layer (6) between the first dielectric substrate (1) and the second conductor ground plane (5), and in a case where the first conductor ground plane (2) is provided on the back surface of the first dielectric substrate (1), the plurality of conductive members (4) functions as spacers for providing an air layer (6) between the first conductor ground plane (2) and the second conductor ground plane (5).