Radar Antenna Mounting Layout for Stable Directional Characteristics
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Solution Overview
Problem
The challenge is to miniaturize radar devices for vehicle cabins while maintaining radio wave directional characteristics, as miniaturization can lead to instability and deterioration of these characteristics due to the proximity of antennas to housing components and screw fastening affecting radio waves.
Innovation Solution
The radar device is designed with array antennas mounted on a substrate, where fastening members secure the cover and case in regions away from the antenna edges, reducing the impact of housing components on radio waves, and using support structures to maintain stability and minimize size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the substrate is miniaturized to reduce device size, then the device achieves miniaturization, but the substrate area becomes insufficient with respect to antenna opening area and radio wave directional characteristics become unstable
Solution Approach 1:
The patent applies local quality by creating an asymmetric ground structure where only specific regions have ground patterns. The ground is selectively provided in regions that do not interfere with antenna radiation, while leaving other regions ground-free to improve radio wave characteristics. This localized differentiation allows miniaturization while maintaining stable directional characteristics.
Solution Approach 2:
The ground structure is segmented into multiple regions with different characteristics. The substrate is divided into a first region with ground pattern and a second region without ground, allowing each region to serve different functions - the grounded region provides stability while the ungrounded region allows proper radio wave propagation.
2Ease of manufacture
If screws are arranged for fastening the cover to the case, then workability and cost are improved, but the shape of the cover for screw arrangement or the presence of screws themselves may affect radio wave characteristics and further deteriorate radio wave directional characteristics
Solution Approach 1:
The patent applies local quality by differentiating screw arrangement strategies based on antenna orientation. For antennas vibrating in the second direction, screws are arranged in first regions away from edges parallel to the first direction. This localized differentiation allows standard screw fastening while protecting radio wave characteristics in critical areas.
3Area of moving object
If the substrate area is reduced for miniaturization, then device size is reduced, but antenna operates closer to housing or substrate ends causing unstable radio wave directional characteristics
Solution Approach 1:
The patent applies local quality by creating asymmetric ground structures where ground is selectively provided only in specific regions. This allows the antenna to operate closer to substrate edges while maintaining stable directional characteristics through strategic ground placement that does not interfere with radiation patterns.
Solution Approach 2:
The patent addresses the two-dimensional substrate area constraint by introducing dimensional differentiation in the ground structure. Instead of uniform ground coverage, the ground is distributed selectively across different regions, effectively using spatial dimensionality to resolve the conflict between miniaturization and radio wave stability.
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 stabilizes radio wave directional characteristics and reduces miniaturization-related instability, allowing for effective detection while maintaining detection area coverage.
Implementation Method 1
a plurality of array antennas each having a plurality of elements arranged in an array that electrically vibrate in a predetermined vibration direction to transmit and receive a detection wave
Data Source
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AI summary
A radar device (10) includes: a plurality of array antennas (16) each having a plurality of elements (16a) arranged in an array that electrically vibrate in a predetermined vibration direction to transmit and receive a detection wave for detecting an object; a substrate (18) having a first surface (18a) on which the array antennas are mountable and a second surface (18b) on a side opposite to the first surface; a case (20) configured to accommodate the substrate and support the second surface; a cover (22) configured to cover, from a side of the first surface of the substrate, the case in a state where the substrate is accommodated; and a fastening member (24) configured to fasten the cover, the substrate, and the case together in a first region (W1) on a side where a distance to a substrate edge parallel to a first direction (D) in the substrate is large with reference to a mounting position on the substrate on which the array antenna (16B) which electrically vibrates in a second direction (E) orthogonal to the first direction in which the elements are arranged, among the array antennas, is mounted.