Planar Antenna Structure with Reduced Coupling Between Arrays
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Solution Overview
Problem
In automotive radar sensor modules, the close proximity of transmit (Tx) and receive (Rx) antenna arrays leads to increased undesirable coupling, degrading antenna performance due to their parallel alignment, which worsens as the arrays are made smaller and spaced closer together.
Innovation Solution
The Tx and Rx arrays are positioned with nonparallel longitudinal axes, tilted at an angle of 2.0 to 5.0 degrees, typically 2.5 degrees, to reduce radiation coupling, with conductive lines connecting adjacent patches also oriented nonparallel to each other, altering polarization and minimizing coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If Tx and Rx antenna arrays are positioned close together to reduce sensor size, then the sensor compactness is improved, but the radiation coupling between arrays increases
Solution Approach 1:
The patent applies asymmetry by positioning the Tx and Rx antenna arrays with nonparallel longitudinal axes, tilted at an angle of 2.0 to 5.0 degrees relative to each other. This asymmetric orientation disrupts the parallel alignment that causes strong coupling, reducing radiation coupling by approximately 3 dB while maintaining compact sensor dimensions.
2Ease of manufacture
If Tx and Rx antenna arrays are aligned parallel to each other for simplified manufacturing, then the manufacturing complexity is reduced, but the radiation coupling between arrays increases
Solution Approach 1:
The patent introduces asymmetric tilting of the antenna arrays, where the longitudinal axes are nonparallel and tilted at 2.0 to 5.0 degrees. This asymmetric configuration reduces coupling while remaining compatible with standard manufacturing processes for planar antenna structures.
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 reduces coupling by approximately 3 dB within the frequency band of interest (76-77 GHz) without altering antenna patterns, improving overall sensor performance and maintaining negligible impact on antenna features.
Implementation Method 1
A spatial orientation of the first array with respect to the second array is selected based on a predetermined desired radiation coupling between the first array and the second array
Data Source
AI summary
An antenna includes a substrate, a first array of transmit antenna patches on the substrate, and a second array of receive antenna patches on the substrate. A spatial orientation of the first array with respect to the second array is selected based on a predetermined desired radiation coupling between the first array and the second array. The antenna can be part of an automotive radar sensor.