MIMO Radar Sub-Array Layout for Virtual Aperture Expansion
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Solution Overview
Problem
Existing radar systems face challenges in expanding the aperture length of virtual reception array antennas while minimizing grating lobes and improving directivity gain, particularly in MIMO radars with limited antenna elements, which affects angular resolution and detection accuracy.
Innovation Solution
A radar apparatus is designed with a sub-array antenna configuration that expands the aperture length of virtual reception array antennas by arranging transmission and reception elements at specific intervals, using time-division multiplexing, and employing sub-arrayed antenna elements to suppress grating lobes and enhance directivity gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the number of antenna elements is increased to expand aperture length, then the aperture length of virtual reception array antenna is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines transmission and reception antenna elements into a shared array structure where the same physical antenna elements serve dual purposes. By time-division multiplexing the transmission and reception functions across shared elements, the system achieves virtual aperture expansion equivalent to having separate transmission and reception arrays, thereby reducing hardware complexity while maintaining large aperture length.
Solution Approach 2:
The patent transitions from physical aperture expansion through adding more elements to virtual aperture expansion through signal processing. By creating virtual reception array antennas through mathematical combination of signals from shared antenna elements, the system achieves extended aperture length in the virtual domain without proportionally increasing physical hardware complexity.
2Area of stationary object
If antenna elements are arranged closer to reduce device size, then the device footprint is reduced, but grating lobes increase and directivity gain decreases
Solution Approach 1:
The patent optimizes the spacing parameter of antenna elements to satisfy specific mathematical relationships (e.g., spacing less than half wavelength). By carefully selecting and adjusting the spacing parameter within constrained ranges, the system suppresses grating lobe formation while maintaining compact device footprint, thereby preserving detection accuracy without excessive size.
Solution Approach 2:
The patent applies different spacing strategies to different regions of the antenna array. By implementing non-uniform spacing or different spacing rules for transmission versus reception elements, the system locally optimizes each region to suppress grating lobes while maintaining overall compactness, thereby improving detection accuracy without uniformly increasing the device footprint.
3Reliability
If antenna elements are arranged at larger intervals to reduce grating lobes, then directivity gain is improved, but the aperture length and device size increase
Solution Approach 1:
The patent employs dynamic beamforming techniques that adaptively adjust the effective aperture utilization based on target direction and detection requirements. By dynamically weighting and combining signals from antenna elements with optimized spacing, the system achieves high directivity gain toward specific directions without requiring the entire physical aperture to be maximally extended, thereby balancing directivity gain with compact aperture length.
4Device complexity
If the number of antenna elements is limited to reduce device complexity, then the device complexity is reduced, but the aperture length and virtual reception array performance are compromised
Solution Approach 1:
The patent introduces signal processing algorithms as an intermediary between the limited physical antenna elements and the desired high-resolution angular measurement. By applying sophisticated beamforming, spectral estimation, or other signal processing techniques to the outputs of fewer antenna elements, the system achieves angular resolution performance equivalent to systems with many more elements, thereby decoupling measurement precision from hardware complexity.
Data Source
AI summary
To provide an improved radar apparatus capable of expanding the aperture length per antenna element and the aperture length of the virtual reception array antenna. One of a transmission array antenna and a reception array antenna includes a first antenna element group having m-pieces of antenna elements arranged at a first interval Dt along a first axis direction (m is an integer of 1 or larger), and the other one of the transmission array antenna and the reception array antenna includes a second antenna element group having (n+1)-pieces of antenna elements arranged at a second interval Dr(n) along the first axis direction (n is an integer of 1 or larger).