Offset Composite Antenna for Spoiler Interference
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Solution Overview
Problem
Conventional vehicle-mounted antennas face issues with signal-to-noise (S/N) characteristics and directivity due to interference with high-mount stop lamps and mutual coupling with sub-antennas, especially when positioned at the center of the spoiler, leading to variations in reception precision.
Innovation Solution
A composite antenna element is designed to be bent and offset-disposed within the vehicle's hollow body, such as a spoiler, with a planar orientation inclined vertically and grounded near a metal portion, avoiding interference with high-mount stop lamps and positioned to reduce mutual coupling, while a sub-antenna is placed on the opposite side to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna is disposed at the center between the left and right ends of the spoiler, then the appearance is not ruined and the antenna is protected, but interference with the high-mount stop lamp occurs and S/N characteristics are worsened
Solution Approach 1:
The antenna element is disposed asymmetrically relative to the vehicle width direction, specifically positioned closer to one side rather than at the center. This asymmetric positioning avoids the high-mount stop lamp located at the center, eliminating interference while maintaining aesthetic appearance and improving S/N characteristics
2Reliability
If the antenna element is disposed at the center between the left and right ends with respect to the vehicle traveling direction, then the structure is simplified, but null occurs in the directivity and gain deteriorates
Solution Approach 1:
The antenna element is positioned asymmetrically in the width direction rather than at the center, which eliminates nulls in the directivity pattern and maintains consistent gain across different reception directions, thereby improving reliability without significantly increasing structural complexity
3Reliability
If a sub-antenna is used to improve reception, then coverage is enhanced, but mutual coupling with the sub-antenna occurs and S/N characteristics are worsened
Solution Approach 1:
The harmful effect of mutual coupling is eliminated by removing the sub-antenna component entirely. The single antenna element is designed to provide sufficient reception precision without requiring an additional sub-antenna, thereby avoiding mutual coupling while maintaining reliable reception
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 improves S/N characteristics and directivity by reducing coupling with the vehicle's metal body and avoiding nulls in reception, maintaining consistent gain across directions.
Implementation Method 1
a composite antenna element (10) that has an antenna length corresponding to a first frequency band and is bent so as to also function as a capacitive antenna corresponding to a second frequency band and to improve an antenna effective capacitance
Implementation Method 2
the composite antenna element is disposed such that a planar direction thereof is inclined toward a vertical-direction side with respect to a metal body of the vehicle
Implementation Method 3
is grounded in a metal portion of the vehicle near a position where the composite antenna element is disposed
Data Source
AI summary
An antenna device that is built inside a hollow body fixed to a vehicle comprises a composite antenna element that has an antenna length corresponding to a first frequency band and is bent so as to also function as a capacitive antenna corresponding to a second frequency band and to improve an antenna effective capacitance and that is disposed in a substantially planar manner. The composite antenna element is disposed such that a planar direction thereof is inclined toward a vertical-direction side with respect to a metal body of the vehicle, and is offset-disposed to a left or right side in the hollow body with respect to a vehicle traveling direction, and is grounded in a metal portion of the vehicle near a position where the composite antenna element is disposed.