Vehicle Antenna Device Suppressing Interference via Non-Resonant Loading
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Solution Overview
Problem
The existing low profile antenna devices for vehicles suffer from decreased gain and increased maximum and minimum gain difference in in-horizontal-plane directivity, particularly when receiving high frequency signals, due to interference from umbrella-type elements.
Innovation Solution
The antenna device features a first and second element installed on an antenna base, where the first element is a patch antenna for a specific frequency band, and the second element is a capacitance loading element with a three-dimensional shape formed by meandered linear conductors, ensuring non-resonant lengths to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If an umbrella-type element with a plate shape is used to increase the area and gain, then the area of the antenna element is improved, but the gain of another antenna element decreases due to interference
Solution Approach 1:
The patent changes the length parameter of the second element from a resonant length to a non-resonant length relative to the first antenna's frequency. This parameter change prevents the second element from interfering with the first antenna's operation, thereby maintaining the first antenna's gain while still allowing the second element to provide its intended function for other frequency bands.
2Stability of the object's composition
If an umbrella-type element with continuous slant portions is used, then the structural continuity is improved, but the maximum and minimum gain difference in in-horizontal-plane directivity increases
Solution Approach 1:
The patent modifies the length parameter of the second element to be a non-resonant length, which changes its electromagnetic characteristics. This parameter change allows the element to maintain structural continuity while preventing it from acting as a resonant structure that would distort the horizontal-plane directivity pattern of the first antenna.
3Adaptability or versatility
If multiple antenna elements for different frequency bands are installed on the same antenna base, then the versatility of the antenna device is improved, but interference between antenna elements occurs
Solution Approach 1:
The patent applies parameter changes by setting the length of the second element to a non-resonant length relative to the first antenna's operating frequency. This prevents the second element from generating harmful electromagnetic interference with the first antenna, while still allowing both elements to function for their respective frequency bands, thus maintaining versatility without interference.
Solution Approach 2:
The second element acts as an intermediary structure that, through its non-resonant length design, mediates between the need for multi-frequency capability and the need to prevent interference. By being neither resonant nor non-resonant with the first antenna's frequency, it serves as a passive structure that doesn't disrupt the first antenna's operation while still providing functionality for other frequency bands.
Data Source
AI summary
There is provided an antenna device for a vehicle capable of suppressing interference in a case where a plurality of antennas which receive signals in different frequency bands are close to one another. The antenna device for the vehicle includes a patch antenna and a capacitance loading element which are installed away from each other on an antenna base section which is attachable to a vehicle. The capacitance loading element is a part of an antenna capable of receiving a different use frequency band from which of the patch antenna, to form a three-dimensional shape in which a pair of linear conductors which respectively repeatedly turn in a predetermined direction are connected to each other via a linear connection conductor extending in a width direction of the antenna base section, and in the capacitance loading element, a length of a folded portion of each of the linear conductors is a non-resonant length of the patch antenna.