Radar Antenna Arrays for Unambiguous Angle Finding
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Solution Overview
Problem
Radar devices face limitations in achieving high angular resolution with a limited number of antennas due to phase shift ambiguities and mutual coupling issues, which hinder accurate detection and separation of objects within their field of view.
Innovation Solution
The radar device employs two sets of antennas with large distances between individual elements, using differential phase shifts from multiple propagation channels to determine a unique target angle, allowing for large apertures and unambiguous angle finding with a limited number of antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between individual antennas is increased to improve angular resolution, then the angular resolution is improved, but phase shift ambiguities occur leading to unambiguous angle finding becoming difficult
Solution Approach 1:
The antenna array is divided into multiple subsets, where each subset provides angle measurements with a specific ambiguity pattern. By segmenting the antenna elements into different groups and processing their measurements separately, the system can resolve ambiguities by finding the common solution across all subsets.
Solution Approach 2:
The problem is transformed from a one-dimensional angle estimation problem into a multi-dimensional optimization problem by introducing multiple antenna subsets. Each subset operates in its own measurement dimension, and the final angle is determined by finding the intersection point across all dimensions, effectively adding a new dimension to the measurement space.
2Measurement precision
If the number of antennas is increased to improve angular resolution, then the angular resolution is improved, but the device complexity and cost increase
Solution Approach 1:
Multiple antenna subsets are merged in a way that their combined measurements provide unambiguous angle finding. Instead of using all antennas simultaneously for direct measurement, the system merges the information from multiple subsets, each with fewer elements, to achieve the same resolution with reduced overall complexity.
Solution Approach 2:
Each antenna element serves multiple functions by belonging to different subsets. The same physical antenna elements are reused across multiple measurement configurations, allowing the system to achieve high angular resolution without proportionally increasing the number of physical antennas required.
3Measurement precision
If the distance between individual antennas is increased to improve angular resolution, then the aperture size is increased, but mutual coupling between antennas increases causing signal degradation
Solution Approach 1:
The antenna subsets are positioned and configured with specific local characteristics that minimize mutual coupling effects. By carefully selecting the spatial arrangement and electrical characteristics of each subset, the system maintains optimal performance while reducing harmful interactions between adjacent antenna elements.
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 approach enhances angular resolution and signal-to-noise ratio, enabling accurate detection and separation of objects by resolving ambiguous angle information through combined angle measurements from multiple sets of antennas.
Implementation Method 1
radar devices usually comprise a signal generator to generate a radar signal, an antenna device for illuminating the target objects with the radar signal and for capturing the radar signal reflected back from the target objects
Implementation Method 2
the angular position of the target object is determined from phase shifts between radar signals that are received by neighboring antennas
Data Source
AI summary
The present disclosure relates to apparatuses and methods for a radar device. For example, an antenna device has a first set of antennas to establish first propagation channels and a second set of antennas to establish second propagation channels. A signal processing device determines a first differential phase shift among first radar signals propagating via the first propagation channels and a second differential phase shift among second radar signals propagating via the second propagation channels. Antennas of the first set are located at positions that generate the first differential phase shift for a first multitude of target angles, and antennas of the second set are located at positions that generate the second differential phase shift for a second multitude of target angles. The processing device determines an angular position of a target object as a unique target angle that is part of the first and second multitude of target angles.