MIMO Radar Antenna Vertical Offset Elevation Angle
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current automotive radar systems can only determine distance and horizontal angles to targets, lacking elevation angle measurement capability, which is essential for avoiding obstacles like bridges or buildings, and increasing the number of antennas to improve elevation resolution significantly increases system cost.
Innovation Solution
A multiple input multiple output (MIMO) antenna configuration with vertically offset transmit-antennas allows for elevation angle determination without increasing the number of antennas, using a combination of vertically arranged radiator elements and a virtual-receive antenna design that maintains half-wavelength spacing to avoid grating lobes and enhance spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of transmit-antennas and receive-antennas is increased to improve elevation resolution, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a vertical dimension offset between transmit-antenna arrangements to enable elevation angle determination. By vertically offsetting the first transmit-antenna arrangement from the second transmit-antenna arrangement, the system creates a three-dimensional antenna configuration that provides elevation resolution without proportionally increasing the total number of antenna elements. This dimensional approach allows the system to achieve 3D spatial capability while controlling hardware complexity.
2Power
If multiple strings or arrays of detector elements are used to increase antenna gain, then power is improved, but grating lobes cause harmful effects
Solution Approach 1:
The patent carefully controls the spacing parameter between vertical arrays within each transmit-antenna arrangement to be approximately half-wavelength. This parameter optimization allows multiple detector element strings to be used for increased gain while suppressing grating lobe formation. The half-wavelength spacing is a critical parameter that balances gain enhancement with grating lobe suppression.
3Object-generated harmful factors
If sub-arrays are overlapped to reduce spacing between phase-centers, then grating lobes are reduced, but device complexity increases due to complex feed structure
Solution Approach 1:
The patent uses vertical offsetting of transmit-antenna arrangements to achieve effective sub-array overlap in the vertical dimension without requiring complex multi-layer feed structures. By offsetting transmit arrangements vertically and using MIMO processing, the system achieves the beneficial effect of reduced phase-center spacing while maintaining a relatively simple planar feed structure.
Solution Approach 2:
The patent replaces the need for complex analog beam-forming hardware with digital signal processing in the MIMO receiver. Instead of using complex multi-layer feed structures for analog beam forming, the system uses digital processing of signals from multiple transmit-antenna arrangements to achieve the same grating lobe suppression effect, substituting mechanical/hardware complexity with computational processing.
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
Enables accurate elevation angle measurement while maintaining cost-effectiveness by doubling the effective width of the receive-antenna without increasing the number of antennas, thereby improving detection range and spatial resolution without the need for complex feed structures.
Implementation Method 1
a receive-antenna configured to detect radar-signals reflected by a target toward the receive-antenna
Implementation Method 2
radar-signals reflected by a target
Data Source
AI summary
A multiple input multiple output (MIMO) antenna (520) for a radar system includes a receive antenna (520), a first transmit-antenna-arrangement (822), and a second transmit-antenna-arrangement (824). The receive-antenna (120) is configured to detect radar-signals (920) reflected by a target toward the receive-antenna (120). The first transmit-antenna-arrangement (822) includes a first vertical-array (870) of radiator elements (136) and a second vertical-array (872) of radiator elements (136). The first transmit-antenna-arrangement (822) is configured so the first vertical-array (870) can be selectively coupled to a transmitter (910) independent of the second vertical-array (872). The second transmit-antenna-arrangement (824) includes a third vertical-array (874) of radiator elements (136) and a fourth vertical-array (876) of radiator elements (136). The second transmit-antenna-arrangement (824) is configured so the third vertical-array (874) can be selectively coupled to a transmitter (910) independent of the fourth vertical-array (876). The second transmit-antenna-arrangement (824) is vertically offset from the first transmit-antenna-arrangement (822) by a vertical offset distance (126) selected so an elevation angle to the target can be determined by the receive-antenna (120).