High Resolution Unambiguous Radar Using Overlapping Virtual Arrays
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Solution Overview
Problem
Automotive radar systems face challenges in achieving high angular resolution and minimizing the number of unique RF chips, which affects antenna placement flexibility and increases cost and complexity, especially at higher operating frequencies.
Innovation Solution
The implementation of a radar system with multiple substantially identical transceiver sets, each comprising transmit and receive chips with uniformly spaced antennas, forming virtual antenna arrays that overlap to enhance angular resolution and reduce ambiguity, while minimizing the number of unique RF chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If antennas are integrated as part of the RF chip at higher frequencies (e.g., 240 GHz), then gain loss is reduced, crosstalk is reduced, and temperature variation robustness is improved, but the number of unique RF chips increases, negatively impacting cost and complexity
Solution Approach 1:
The antenna array is divided into multiple sub-arrays, with each sub-array implemented on a separate RF chip. This segmentation allows the system to achieve high angular resolution through multiple sub-arrays while avoiding the need for a single complex chip with many antennas, thus reducing gain loss and crosstalk without proportionally increasing the number of unique RF chips.
Solution Approach 2:
Multiple sub-arrays are designed with identical or similar antenna configurations and are coupled to the same RF chip architecture. This universality allows the system to use repeated, standardized chip designs rather than unique chips for each antenna, reducing the number of unique RF chips needed while maintaining high angular resolution through the combined array.
2Measurement precision
If a large number of antennas are used to achieve high angular resolution, then angular resolution is improved, but the number of connecting traces between antennas and RF chip increases, making signal processing impractical on a single RF chip
Solution Approach 1:
The large antenna array is segmented into multiple smaller sub-arrays, each connected to the RF chip through a manageable number of traces. This segmentation makes the connecting trace problem practical while maintaining high angular resolution through the combined effect of multiple sub-arrays.
Solution Approach 2:
The system transitions from a two-dimensional planar array to a three-dimensional configuration by stacking multiple sub-arrays in different spatial dimensions. This dimensional change allows high angular resolution to be achieved through spatial distribution rather than through an increased number of connecting traces on a single chip plane.
3Adaptability or versatility
If antenna placement flexibility is increased with external antennas, then degrees of freedom in antenna placement is improved, but the system becomes more sensitive to accurate position requirements at higher frequencies
Solution Approach 1:
The antenna system is divided into multiple sub-arrays that can be independently positioned and configured. Each sub-array maintains internal position accuracy while the overall system gains placement flexibility through the ability to distribute sub-arrays across different locations and orientations.
Solution Approach 2:
Multiple sub-arrays with individually flexible placements are merged into a unified virtual array through signal processing. This merging allows the system to achieve both placement flexibility and position accuracy by combining the positional information from multiple sub-arrays into a coherent high-resolution angular measurement.
Data Source
AI summary
A radar system and method include and employ a plurality of substantially identical transceiver sets establishing respective substantially identical, overlapping virtual antenna arrays. A first sub-array of widely spaced virtual antennas provides high angular resolution but high angular ambiguity. A second sub-array of narrowly spaced virtual antennas provides low angular ambiguity but low angular resolution.