MIMO Radar Antenna Spacing for Wider Aperture and Fewer Grating Lobes
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Solution Overview
Problem
Current MIMO radar systems face challenges in expanding the aperture length of virtual reception array antennas, leading to restricted angular resolution and increased probability of misdetection due to physical interference and grating lobe generation, especially when antenna elements are disposed equidistantly at half-wavelength intervals.
Innovation Solution
The proposed radar apparatus configures transmission and reception array antennas with specific intervals and sub-array antenna configurations, allowing for the expansion of aperture length while suppressing grating lobe generation and improving directivity gain by using a sub-array antenna configuration and applying array weights to reduce side lobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If antenna elements are disposed equidistantly at half-wavelength intervals to form a virtual reception array antenna, then the aperture length can be expanded, but grating lobe generation occurs and causes misdetection
Solution Approach 1:
The patent applies asymmetry by disposing antenna elements at non-uniform intervals. Specifically, the reception antenna elements are arranged with different spacing distances rather than equidistant half-wavelength intervals. This asymmetric arrangement suppresses grating lobe generation while maintaining an expanded aperture length, thereby improving detection reliability without sacrificing the aperture expansion benefit
Solution Approach 2:
The patent changes the spatial parameter (interval distance) of antenna element arrangement from the conventional fixed half-wavelength equidistant spacing to variable non-uniform spacing. By adjusting the interval parameters between adjacent antenna elements, the system achieves both aperture expansion and grating lobe suppression, resolving the contradiction between aperture length and misdetection probability
2Device complexity
If antenna elements are disposed equidistantly at half-wavelength intervals, then the array configuration is simple, but the main lobe width is wide and angular resolution is poor
Solution Approach 1:
The patent uses asymmetric non-uniform spacing of antenna elements to achieve narrower main lobe width and improved angular resolution. The varying intervals between adjacent elements create a more focused beam pattern compared to equidistant arrangements, enhancing measurement precision while maintaining reasonable configuration complexity
Solution Approach 2:
By changing the spatial interval parameters from fixed half-wavelength to variable non-uniform values, the patent optimizes the main lobe width and angular resolution. The specific interval values are selected to achieve better directional resolution without making the configuration excessively complex
3Length of stationary object
If the number of antenna elements is increased to expand aperture length, then angular resolution improves, but physical interference increases and system complexity rises
Solution Approach 1:
The patent transitions from uniform one-dimensional equidistant spacing to non-uniform spacing in the same dimension, effectively using the spatial arrangement dimension to achieve aperture expansion without simply increasing the number of elements. This dimensional reconfiguration allows aperture length expansion while controlling system complexity
Solution Approach 2:
The patent changes the arrangement parameters of existing antenna elements from fixed equidistant spacing to variable non-uniform spacing. This parameter optimization allows the system to achieve effective aperture length expansion and improved angular resolution without necessarily increasing the number of antenna elements, thereby controlling system complexity
Data Source
AI summary
A radar apparatus includes a radar transmission circuit that transmits a radar signal from a transmission array antenna, and a radar reception circuit that receives, from a reception array antenna, a reflected wave signal that is the radar signal reflected at a target. One of the transmission array antenna and the reception array antenna includes a first antenna element group having m antenna elements arranged at a first interval Dt along a first axis direction, wherein m is an integer of 2 or larger. The other one of the transmission array antenna and the reception array antenna includes a second antenna element group having n antenna elements arranged at a second interval Dr along the first axis direction, wherein n is an integer of 4 or larger. The second interval Dr includes several different intervals.