Vehicle Antenna Layout Avoiding Standing-Wave Voltage Peaks
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Solution Overview
Problem
In vehicle-mounted antenna devices, maintaining sufficient distance between multiple antennas within a limited space is challenging, leading to decreased antenna gain, while increasing the distance results in a larger case size.
Innovation Solution
The antenna device incorporates a second plate-shaped antenna above a first antenna, with the first antenna positioned to avoid voltage maximum points of the second antenna's standing waves, and uses a helical element and filter components to optimize antenna placement and electrical connections, allowing for downsizing without compromising antenna gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple antennas are provided within a limited space in a case, then the antenna device can be downsized, but the distance between antennas cannot be sufficiently maintained and antenna gain decreases
Solution Approach 1:
The patent positions the second plate-shaped antenna above the first antenna in the vertical dimension, rather than placing them side-by-side in the horizontal plane. This three-dimensional arrangement allows multiple antennas to coexist in a compact case volume while maintaining sufficient spatial separation to preserve antenna gain and reduce mutual interference.
2Reliability
If the distance between antennas is increased inside a case, then antenna gain is maintained, but the case becomes large and cannot be downsized
Solution Approach 1:
By utilizing the vertical dimension for antenna placement, the patent achieves both compact case size and sufficient antenna separation. The plate-shaped second antenna is positioned above the first antenna at a controlled distance that maintains gain while minimizing overall case volume.
Solution Approach 2:
The patent optimizes the vertical distance between the first and second antennas as a key parameter. By carefully controlling this separation distance, the design maintains sufficient isolation to preserve antenna gain while keeping the overall case size compact and suitable for vehicle installation.
3Volume of moving object
If the first antenna is positioned near the second antenna to downsize the case, then case size is reduced, but the first antenna overlaps with voltage maximum points of the second antenna's standing wave and gain decreases
Solution Approach 1:
The patent resolves positioning precision challenges by moving the first antenna to a different vertical level below the second antenna. This three-dimensional separation eliminates overlap with voltage maximum points of the second antenna's standing wave, ensuring optimal gain while maintaining compact case 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
This configuration enables a compact antenna device with maintained or improved antenna gain by strategically positioning and connecting multiple antennas within a common case, balancing size reduction and performance.
Implementation Method 1
the first antenna is arranged so as to avoid a voltage maximum point of a standing wave, of a frequency band of the first antenna, generated in the second antenna
Implementation Method 2
a second plate-shaped part electrically connected to the first plate-shaped part through a filter part that cuts off the frequency band of the first antenna
Data Source
AI summary
An antenna device which includes a plurality of antennas in a common case and is capable of achieving downsizing while suppressing a decrease of an antenna gain, is provided. An antenna device includes a TEL antenna and a capacity loaded element in a common case. The capacity loaded element is located above the TEL antenna. A length of the capacity loaded element is a positive integer multiple of one-half a wavelength of a PCS band. The TEL antenna is arranged so as to avoid a voltage maximum point of a standing wave, of the PCS band, generated in the capacity loaded element.