Polarization Ratio DOA Detection With a Compact 2×2 Antenna Array
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Solution Overview
Problem
Conventional methods for detecting the direction of arrival of target signals using antenna arrays require large antenna apertures and numerous RF and digital-to-analog converter channels, leading to increased system cost and size, making it difficult to achieve high resolution in two dimensions without a significant increase in the number of elements.
Innovation Solution
A method and system using a 2×2 antenna array with independently controllable right-handed and left-handed circular polarization beams to form a co-polarization and cross-polarization pattern ratio map, allowing for high-resolution direction of arrival detection by normalizing and matching these ratios to identify potential signal directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional antenna arrays use large aperture sizes to achieve high resolution, then measurement precision improves, but device complexity and system cost increase dramatically
Solution Approach 1:
The patent transitions from conventional spatial aperture dimension to polarization dimension by utilizing orthogonal co-polarization and cross-polarization patterns. Instead of increasing the number of antenna elements in space, the invention uses polarization diversity to create virtual aperture extensions, achieving high resolution with a compact 2×2 physical array configuration.
Solution Approach 2:
The invention changes the operational parameters by forming multiple beams with different polarization states (co-polarization and cross-polarization) from the same physical antenna elements. By varying the polarization parameters and forming ratio maps of Co-pol to X-pol patterns, the system achieves enhanced direction finding capability without adding physical elements.
2Measurement precision
If the number of RF and digital-to-analog converter channels is increased to improve resolution, then measurement precision improves, but loss of substance increases due to more components
Solution Approach 1:
Each antenna element in the 2×2 array is designed to perform multiple functions: transmitting and receiving signals, generating both co-polarization and cross-polarization patterns, and forming multiple beams simultaneously. This multi-functionality eliminates the need for separate dedicated channels for each polarization and beam direction, reducing the total number of RF and ADC channels required.
Solution Approach 2:
The patent merges the functions of multiple separate antenna elements and channels into a compact 2×2 array where each element handles multiple polarization states. By combining co-polarization and cross-polarization reception at each element and processing their ratios, the system consolidates what would traditionally require many separate channels into a minimal set of shared resources.
3Measurement precision
If antenna aperture size is doubled to reduce resolution requirement by factor of 2, then measurement precision improves, but device complexity increases
Solution Approach 1:
Instead of increasing the physical aperture length in space, the invention extends the effective aperture by utilizing the polarization dimension. The orthogonal polarization patterns provide additional spatial discrimination capability, effectively creating a virtual aperture that achieves the same resolution enhancement without increasing physical dimensions.
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
The method achieves comparable resolution to conventional 16×16 arrays using a 2×2 array, reducing the number of elements by at least 98% and providing additional nulling capabilities, while maintaining accurate direction finding in two dimensions.
Implementation Method 1
Radio frequency (RF) sensing is a technique for sensing objects or movement in an environment based, at least in part, on the transmission and reception of electromagnetic signals
Implementation Method 2
independently controllable right-handed and left-handed circular polarization beams
Data Source
AI summary
There is provided a system and method of detecting a direction of arrival of one or more target signals using an antenna array, the method comprising, i) generating a map representing a ratio of a co-polarization (Co-pol) pattern received by the first beam to a cross-polarization (X-pol) pattern received by the second beam; ii) obtaining Co-pol and X-pol signal strengths of the one or more target signals received by the first and second beams in step (i); iii) obtaining the Co-pol to X-pol ratio of each of the one or more target signals; iv) normalizing the generated map; v) normalizing the Co-pol to X-pol ratios of the one or more target signals; and vi) for each target signal: finding area(s), within the normalized generated map, which substantially match the normalized Co-pol to X-pol ratio of the target signal; and identifying said area(s) of the normalized generated map as potential direction(s) of arrival of the target signal.