In-Vehicle Radar Antenna Aperture Expansion
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Solution Overview
Problem
In-vehicle mount radar devices face limitations in enhancing angle resolution and calculation precision due to restricted antenna size, especially when using digital beam forming techniques, where the antenna aperture diameter is not effectively increased beyond a certain point.
Innovation Solution
The in-vehicle mount radar device configures two transmission antennas and a reception antenna array with reception antennas spaced at interval d, while the transmission antennas are positioned at intervals D, where D is set to be larger than d, effectively increasing the antenna aperture diameter and improving angle information calculation precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the antenna aperture diameter is increased to enhance angle resolution, then the angle resolution is improved, but the device size and complexity increase
Solution Approach 1:
The patent transitions from a single-plane antenna arrangement to a three-dimensional configuration by placing transmission antennas at both ends of the reception antenna array along the arrangement direction. This spatial dimensionality change effectively doubles the antenna aperture diameter without proportionally increasing the physical footprint, thereby enhancing angle resolution while controlling device size.
2Measurement precision
If mechanical scanning is used to obtain angle information, then angle information can be obtained, but the device becomes complex and less resistant to vibration
Solution Approach 1:
The patent replaces the mechanical scanning system with a digital beam forming (DBF) processing system. Instead of physically moving the antenna to scan for targets, the invention uses multiple reception antennas with different time delays to electronically form beams in different directions. This substitution eliminates the driving mechanism, reduces device complexity, and improves vibration resistance while maintaining angle information acquisition capability.
3Measurement precision
If analog phase shifters are used in phased array radar, then angle information can be obtained, but the cost increases
Solution Approach 1:
The patent substitutes analog phase shifters with digital signal processing in the DBF system. Instead of using expensive analog phase shifting components for each antenna element, the invention implements phase control through digital time delay processing. This digital approach reduces component count and cost while achieving the same angle measurement precision through computational methods.
4Volume of moving object
If reception antennas are arranged with small interval to fit limited space, then the device becomes compact, but the angle resolution deteriorates
Solution Approach 1:
The patent resolves this contradiction by utilizing the third dimension (depth along the arrangement direction) to increase the effective aperture. By placing transmission antennas at both ends of the reception array with interval D larger than the reception antenna interval d, the system creates a virtual extended aperture of 2D. This allows compact in-plane arrangement while achieving high angle resolution through the extended effective aperture in the arrangement direction.
Data Source
AI summary
In an in-vehicle mount radar device which has a reception antenna array containing plural reception antennas and two transmission antennas and in which a transmission pulse is time-divisionally and alternately transmitted from each of the two transmission antennas, a reception pulse based on the transmission pulse reflected from a target is received by each of the reception antennas, and at least angle information concerning the target is calculated by using reception data obtained by each reception antenna, the reception antenna array is constructed by arranging the plural reception antennas so that the reception antennas are spaced from one another at an interval d, each of the two transmission antennas is disposed so as to be spaced from the reception antenna located at each of both the end portions of the reception antenna array at an interval D, and the interval D is set to any value larger than the interval d.