Flat-Beam Antenna Wave Guide for Automotive Radar Noise Reduction
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Solution Overview
Problem
Doppler sensors or radars for automobiles face challenges in generating a wide flat beam in the horizontal direction while maintaining a narrow flat shape in the vertical direction to reduce noise and extend detection distance, due to issues with feed line length and antenna gain.
Innovation Solution
The design incorporates a radiation source on a substrate with a wave guide that radiates electromagnetic waves as a beam, with a radiation-side opening having orthogonal directions, where the second direction is longer than the first, allowing for efficient generation of a flat beam suitable for sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a feed line is used to supply power to antenna elements, then the antenna can be constructed with multiple elements, but the feed line length increases causing transmission loss and reduced antenna gain
Solution Approach 1:
The patent extracts and eliminates the feed line from the antenna structure by using a ground reflection type configuration where the ground plane itself serves as the reference, removing the source of transmission loss while maintaining the multi-element antenna construction
2Object-affected harmful factors
If the beam width in the vertical direction is reduced to reduce noise, then detection sensitivity in the vertical direction improves, but the field of view in the horizontal direction is limited
Solution Approach 1:
The patent applies asymmetry by configuring the antenna elements and ground plane to create an asymmetric radiation pattern that produces a narrow beam in the vertical direction for noise reduction while maintaining a wide beam in the horizontal direction for extended field of view
Solution Approach 2:
The patent uses the ground plane reflection to create a three-dimensional radiation pattern where the vertical dimension is controlled for noise reduction while the horizontal dimension maintains wide coverage, effectively using dimensional separation to resolve the contradiction
3Loss of energy
If the focal length is increased to reduce feed line loss, then transmission loss decreases, but the antenna structure becomes larger and cannot generate a flat beam
Solution Approach 1:
The patent removes the focal length requirement by eliminating the traditional feed line structure and using direct ground reflection, allowing compact antenna dimensions while maintaining low transmission loss and achieving flat beam generation
Solution Approach 2:
The patent replaces the mechanical feed line transmission system with an electromagnetic field-based ground reflection system, eliminating the need for long focal lengths and enabling compact flat beam antenna design
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 the generation of a flat beam that enhances detection sensitivity and reduces noise, improving the sensor's ability to detect targets over a wider area while minimizing unnecessary radiation.
Implementation Method 1
The wave guide internally propagates electromagnetic waves radiated from the radiation source and radiates the electromagnetic waves as a beam
Implementation Method 2
By using the horn 16 and the dielectric lens 4, antenna gain improves by collecting electromagnetic waves radiated from one patch antenna 16
Data Source
AI summary
A sensor has an antenna. The antenna includes a radiation source and a wave guide. The radiation source is formed on a substrate. The wave guide internally propagates electromagnetic waves radiated from the radiation source and radiates the electromagnetic waves as a beam. The wave guide has a radiation-side opening in which a first direction and a second direction are orthogonal to each other, and the second direction is longer than the first direction. In a cross-sectional shape of the beam, perpendicular to a radiation direction of the beam radiated from the wave guide, a first direction and a second direction are orthogonal to each other, and the second direction is narrower than the first direction.