Dual-Array MIMO Radar Beamforming for Higher Angular Accuracy
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Solution Overview
Problem
Existing MIMO radar systems have limited angular accuracy due to wide beam widths, which is insufficient for many applications, and increasing the inter-element distance to achieve narrower beams is not feasible due to constraints on grating lobes and side lobes.
Innovation Solution
The MIMO radar system employs two antenna arrays with different inter-element distances, where the first array generates beam patterns with single main lobes, and the second array generates beam patterns with multiple lobes, allowing for a combined beam pattern that achieves higher angular resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the inter-element distance is increased to achieve narrower beam width, then angular accuracy is improved, but grating lobes and side lobes cannot be suppressed
Solution Approach 1:
The patent divides the antenna array into two separate sub-arrays with different inter-element distances. The first sub-array uses a smaller inter-element distance to suppress grating lobes, while the second sub-array uses a larger inter-element distance to achieve narrower beam width and higher angular accuracy. This segmentation allows each sub-array to optimize for its specific function without compromising the other.
Solution Approach 2:
Different regions of the antenna array (the two sub-arrays) are assigned different local properties - specifically, different inter-element distances. The first sub-array has a local property optimized for grating lobe suppression, while the second sub-array has a local property optimized for beam narrowness. This local differentiation resolves the contradiction by allowing each region to excel at its specific task.
2Measurement precision
If additional elements are added to increase effective aperture for narrower beams, then angular accuracy is improved, but device complexity increases
Solution Approach 1:
Instead of simply adding more antenna elements to increase effective aperture, the patent changes the parameter of inter-element distance in the second sub-array. By increasing the inter-element distance, the beam width is reduced and angular accuracy is improved without necessarily increasing the total number of elements. This parameter change provides an alternative path to improved performance that avoids the complexity penalty of adding elements.
3Object-generated harmful factors
If the transmission and reception arrays are designed with standard inter-element distances, then grating lobes are suppressed, but beam width becomes wide and angular accuracy is limited
Solution Approach 1:
The patent segments the antenna array into two functional sub-arrays. The first sub-array maintains standard inter-element distance for grating lobe suppression, while the second sub-array uses increased inter-element distance for narrow beam width. This segmentation allows the system to achieve both grating lobe suppression and high angular accuracy simultaneously.
Solution Approach 2:
The antenna array functions as a composite structure combining two different sub-array configurations. Just as composite materials combine different materials to achieve superior properties, this composite antenna structure combines two different inter-element distance configurations to achieve both grating lobe suppression and narrow beam width, resolving the contradiction between these two requirements.
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 allows for a narrower beam width and higher angular accuracy for target localization, while maintaining good coverage within the field of view, and enables the selection of cross-channels to control the field of view with higher resolution.
Implementation Method 1
One antenna is used to transmit an electromagnetic pulse into the space around the vehicle. This pulse will reflect from objects in the vicinity of the vehicle. Another antenna, or the same antenna, is used to receive the reflections.
Implementation Method 2
The time it takes for reflections to return and the frequency shift of the reflections can be used to obtain information on the range and speed of the reflecting objects.
Implementation Method 3
the first beamforming network is configured to generate for each of the first beam ports a different first beam pattern; a first antenna array comprising the first antenna elements configured to transmit or receive first beam patterns of the first beam ports
Data Source
AI summary
The present disclosure relates to a MIMO radar system, comprising a first beamforming network (6) comprising a first beam ports (7A) and antenna ports (7B), wherein the first beamforming network is configured to connect the first beam ports via the first antenna ports to the first antenna elements, wherein the first beamforming network is configured to generate for each first beam port a single beam pattern. The first antenna elements transmitting or receiving a single beam pattern selected from the number of single beam patterns, wherein the first antenna elements are spaced apart at a first distance selected to provide a beam pattern of the first antenna array essentially consisting of a plurality of single main lobes. The radar system also has a similar second beamforming network (8). The second antenna elements of which are spaced apart at a second distance, larger than the first distance, the second distance being selected to provide a beam pattern of the second antenna array essentially consisting of multiple main lobes and multiple side lobes.