Point Symmetrical Antenna Device for Compact Vertical Polarization
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Solution Overview
Problem
Existing nondirectional vertical polarization antennas are large and unstable, requiring significant size and a holding member due to complex current cancellation, making size reduction difficult.
Innovation Solution
A point symmetrical antenna device with a plate-shaped element opposing a grounded wiring board, featuring grounding and feeding leg parts arranged in a regular polygonal shape, and a cutout design that promotes loop current distribution to avoid cancellation, allowing for a smaller size while maintaining operational length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional vertical polarization monopole or dipole antenna is used, then nondirectional radiation in horizontal plane is achieved, but the antenna height increases to approximately λ/4 to λ/2
Solution Approach 1:
The patent transitions from a conventional vertical monopole/dipole configuration to a planar inverted-F antenna structure that operates in the horizontal plane. The antenna element is folded back toward the ground plane, creating a compact planar structure instead of extending vertically, thereby reducing height while maintaining electrical length for λ/4 resonance.
Solution Approach 2:
The antenna element is folded back and nested closer to the ground plane, with the radiating element positioned above the ground plane at a reduced height. This nesting approach allows the antenna to achieve its required electrical length within a compact vertical space, reducing the overall device height.
2Stability of the object's composition
If a monopole or dipole antenna is used, then vertical polarization is achieved, but the antenna shape is unstable and requires a holding member
Solution Approach 1:
The patent integrates the antenna element, feeding structure, and grounding system into a single planar configuration. The inverted-F structure combines the radiating element and ground plane into one stable assembly that can be mounted directly to the vehicle roof without requiring separate holding members, as the entire structure provides mutual mechanical support.
Solution Approach 2:
The antenna is divided into distinct functional segments (radiating element, feeding point, ground plane) that are arranged in a stable planar configuration. This segmentation allows each component to be optimized for its function while maintaining overall structural stability through the planar layout.
3Volume of moving object
If the antenna size is reduced below conventional dimensions, then compactness is improved, but current cancellation occurs in a complicated manner
Solution Approach 1:
The patent employs an asymmetric inverted-F configuration where the antenna element is folded at a specific point creating unequal segments. This asymmetric structure prevents the formation of symmetric current cancellation patterns that occur in conventional compact antennas, ensuring reliable current distribution along the radiating element while maintaining compact dimensions.
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
The antenna device achieves a size reduction of approximately 38% compared to conventional structures while maintaining nondirectional vertical polarization radiation characteristics, enabling a more compact and stable design.
Implementation Method 1
a plate-shaped antenna element arranged to oppose a wiring board that is grounded, with a gap formed therebetween
Data Source
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AI summary
An antenna device is provided with a plate-shaped grounded wiring board 100, a plate-shaped antenna element 110 arranged to oppose the wiring board 100 and spaced apart therefrom, two grounding leg parts 120 which are disposed at ends of the antenna element 110 and each of which has an extending tip connected to the wiring board 100, and a feeding leg part 130 which is disposed at an end of the antenna element 110 and which has an extending tip that connects to a circuit 150 (a transmission circuit or a reception circuit). A planar shape formed by the ends at which the plurality of grounding leg parts 120 are disposed and the end at which the feeding leg part 130 is disposed has point symmetry.