Vehicle Radar Antenna Mounting on Laminated Windshield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radar devices installed inside vehicles experience reduced efficiency in transmission and reception due to attenuation and absorption by the windshield, particularly with short-wavelength radio waves, and statutory limitations on high-frequency oscillator output restrict monitoring distance.
Innovation Solution
The radar device is mounted directly or indirectly on the inner surface of laminated vehicle windshields, utilizing a configuration with an innermost glass layer, an intermediate resin layer, and an outermost glass layer, where the antenna transmits and receives millimeter waves with a vertical polarization component greater than the horizontal component, and the thickness of the intermediate resin layer is optimized to suppress reflection using specific refractive index and thickness relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radar device is installed in the interior of a vehicle, then the radar can be protected from wind and rain, but the radar wave is attenuated by being reflected and absorbed by the windshield
Solution Approach 1:
A dielectric intermediate element is introduced between the windshield and the antenna to act as a mediator. This intermediate element adjusts the electrically effective distance between the glass and the antenna to several times the half-wavelength of the radio wave, thereby suppressing the reflection of radio waves on the glass and reducing attenuation.
Solution Approach 2:
The patent changes the physical parameters of the system by adjusting the distance between the antenna and the windshield to specific values (several times the half-wavelength). This parameter adjustment transforms the reflective interference into a constructive arrangement that minimizes signal loss.
2Measurement precision
If a short-wavelength radio wave is used to improve the resolution of the radar, then the resolution is improved, but the radar wave is more strongly attenuated by the windshield
Solution Approach 1:
The dielectric intermediate element serves as a mediator that is particularly effective for short-wavelength radio waves. By positioning this element at a distance of several times the half-wavelength from the glass, it suppresses reflection more effectively for shorter wavelengths, thereby maintaining both high resolution and low attenuation.
3Length of stationary object
If the output of the high-frequency oscillator is increased to extend monitoring distance, then the monitoring distance is extended, but statutory regulations limit the maximum output
Solution Approach 1:
The patent converts the harmful effect of glass reflection into a beneficial arrangement by deliberately positioning the antenna at a distance of several times the half-wavelength from the glass. This transforms the reflective interference into a configuration that minimizes signal loss, thereby extending monitoring distance without increasing oscillator power.
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 effectively suppresses the reduction in radio wave efficiency, enhancing the monitoring distance and accuracy of radar systems for collision avoidance and driving assistance applications.
Implementation Method 1
a dielectric intermediate element is disposed between glass and the radiating surface of an antenna in order to suppress the reflection of a radio wave on the glass
Implementation Method 2
the electrically effective distance between the glass and the antenna is adjusted to several times the half-wavelength of the radio wave
Implementation Method 3
an antenna part for transmitting a transmission wave from inside the innermost glass layer to outside the outermost glass layer, the transmission wave being a radio wave in a millimeter waveband
Implementation Method 4
receiving a received wave that enters inside the innermost glass layer from outside the outermost glass layer
Data Source
AI summary
A vehicle includes laminated glass located between a vehicle interior and an outside, and an on-vehicle radar device fixed to an inner surface of the laminated glass, a rear-view mirror, or a ceiling. The laminated glass includes an innermost glass layer, an outermost glass layer, and an intermediate resin layer. The on-vehicle radar device includes an antenna part that includes a transmitting antenna for transmitting a transmission wave. Reflection of the transmission wave on the laminated glass will be suppressed by selecting optimum values for the incident angle of the transmission wave on the innermost glass layer and the refractive index and thickness of each layer.