Vehicle Window Antenna Capacitive Coupling
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Solution Overview
Problem
Existing vehicle window glass antennas with conductive films face challenges in resonating at predetermined frequencies due to variations in slot size between the vehicle body flange and conductive film, requiring precise placement and suffering from reduced conductive film effectiveness when bent, which complicates mass production and precision.
Innovation Solution
A vehicle window glass with a conductive film and intermediate films laminated between glass plates, featuring a slot on the conductive film that is capacitively coupled with electrodes, allowing for resonance at a predetermined frequency without precise placement and reducing the need for a slot between the vehicle body flange and conductive film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a slot antenna is formed using the slot between the vehicle body flange and the conductive film, then the antenna can receive radio waves, but the slot size varies due to individual differences in glass plates and bonding agent thickness, making it difficult to resonate at predetermined frequencies and requiring precise placement
Solution Approach 1:
A dielectric substrate is introduced as an intermediary component between the conductive film and the vehicle body flange. This dielectric substrate serves as a mediator that stabilizes the slot dimensions and electromagnetic field distribution, allowing the antenna to resonate at predetermined frequencies without requiring precise control of the bonding agent thickness or glass plate variations.
Solution Approach 2:
The invention changes the physical parameters of the antenna structure by introducing a dielectric substrate with specific permittivity properties. This parameter change allows the slot antenna to maintain consistent resonance characteristics despite variations in assembly tolerances, effectively decoupling the resonance frequency from the slot size variations caused by manufacturing tolerances.
2Power
If the conductive film is made large to improve antenna performance, then the antenna gain increases, but the glass plate requires precise placement and the bonding process becomes more complex
Solution Approach 1:
The dielectric substrate acts as an intermediary that allows the conductive film to be larger in area for improved antenna gain without proportionally increasing the complexity of placement precision requirements. The dielectric substrate provides a stable reference plane that maintains electromagnetic field distribution even with larger conductive film areas.
3Measurement precision
If the slot size is reduced to achieve precise resonance, then the antenna can resonate at predetermined frequencies, but the slot between the flange and conductive film becomes difficult to control in mass production
Solution Approach 1:
The dielectric substrate serves as a manufacturable intermediary component that can be precisely controlled in its own dimensions while compensating for variations in assembly. This allows the slot antenna to achieve precise resonance frequency accuracy without requiring the same level of precision in the slot between the flange and conductive film, thereby improving mass production feasibility.
Solution Approach 2:
The antenna structure is segmented into distinct components: the conductive film, the dielectric substrate, and the vehicle body flange. This segmentation allows each component to be manufactured and controlled independently, with the dielectric substrate serving as the precision reference that ensures resonance frequency accuracy without requiring precise control of the gaps between other components.
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 solution enables antennas to resonate at specific frequencies regardless of slot size variations, simplifies production by eliminating precision requirements, and improves antenna gain and bandwidth while maintaining design aesthetics.
Implementation Method 1
a slot (23) on the conductive film (13) and a pair of electrodes (16) disposed on the vehicle-interior side surface of the glass plate (12), with the first coupled part (21) capacitively coupled to the electrode (16A) through the glass plate (12) and the intermediate film (14B), and the second coupled part (22) capacitively coupled to the electrode (16B) through the glass plate (12) and the intermediate film (14B)
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A vehicle window glass has a glass plate 11, a conductive film 13 laminated on the glass plate 11 and an antenna structured with a feeding structure placed on the conductive film 13, and is characterized in that the feeding structure has a dielectric 12 and a pair of electrodes 16, that the conductive film 13 has a slot 23 one end of which makes an upper edge 13a of the conductive film 13 an open end, and is disposed between the glass plate 11 and the dielectric 12, and that the pair of electrodes 16 are disposed on the opposite side of the side of the conductive film 13 with the dielectric 12 in between so that the slot 23 is sandwiched between the pair of electrodes 16 when the pair of electrodes 16 are projected onto the conductive film 13, and are capacitively coupled to the conductive film 13.