Wideband Antenna Array With Non-Linear Polarization Slots
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Solution Overview
Problem
Existing ultra wideband antenna arrays face challenges in accurately estimating the Angle of Arrival (AoA) of impinging radio waves due to mutual coupling between antennas, which introduces ambiguity and dependence on the polarization of the wave, making it difficult to achieve precise location calculation of the signal source.
Innovation Solution
The design of an antenna array with non-linearly polarized slot elements, optimized inter-element spacing, and controlled phase linearity and group delay angular variation, where each slot has axes ranging from 0.05 to 0.2 times the operating wavelength, minimizes the influence of mutual coupling and polarization dependence, allowing for precise AoA estimation across a broad bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional linearly polarized antenna elements are used, then the radiation pattern is affected by mutual coupling, but the array structure remains simple
Solution Approach 1:
The patent employs asymmetric slot antenna elements with non-linear polarization characteristics. The slots are designed with specific geometric asymmetry (different lengths along orthogonal axes) to achieve non-linear polarization, which fundamentally changes the radiation pattern behavior and reduces sensitivity to mutual coupling effects, thereby improving AoA estimation accuracy
Solution Approach 2:
The patent systematically varies key parameters of the slot elements including slot length, slot width, slot orientation angles, and inter-element spacing. By optimizing these parameters within specific ranges (e.g., slot lengths of 0.05-0.2 times operating wavelength), the array achieves reduced polarization dependence and improved measurement precision without excessive complexity
2Measurement precision
If the array length is increased to reduce mutual coupling effects, then the measurement accuracy improves, but the device size becomes unacceptable
Solution Approach 1:
The patent optimizes the inter-element spacing parameter within a compact range (0.25-0.75 times the operating wavelength) rather than using traditional larger spacings. This parameter optimization, combined with the non-linear polarization design, achieves reduced mutual coupling effects and improved measurement accuracy while maintaining a compact array length suitable for practical applications
Solution Approach 2:
The asymmetric slot design creates a radiation pattern that is inherently less sensitive to inter-element spacing variations and mutual coupling. This allows the use of smaller inter-element spacings without sacrificing measurement accuracy, thereby reducing the overall array length while maintaining performance
3Measurement precision
If dummy elements are added to cancel mutual coupling effects, then the PDoA measurement accuracy improves, but the number of elements and array complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for dummy elements by fundamentally changing the polarization characteristics of the active elements. The non-linear polarization design inherently reduces mutual coupling sensitivity, allowing accurate PDoA measurement with only the minimum necessary active elements, thereby removing the need for additional dummy elements and reducing overall array complexity
Solution Approach 2:
The asymmetric slot configuration creates a radiation pattern with reduced polarization dependence that naturally compensates for mutual coupling effects without requiring symmetric dummy elements. This asymmetric design achieves the same goal as dummy elements but with fewer total elements and simpler array structure
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 results in a wideband linear array with minimal PDoA variation due to polarization, enabling precise radio distance estimation and integration into compact devices, while maintaining signal fidelity and reducing distortions across the operating bandwidth.
Implementation Method 1
each antenna element comprises a slot, the slot being shaped such that the polarisation of the corresponding antenna element is non-linear
Implementation Method 2
The AoA can be estimated by measuring the Phase Difference of Arrival (PDoA) at the outputs of two or more receiving antennas
Data Source
AI summary
An antenna array (10) for detecting an incoming radio wave (52) having an operating wavelength, comprising: a plurality of antenna elements (12) arranged in an array with a periodic repetition of the antenna elements (12). Each antenna element (12) comprises a slot (32) being shaped such that the polarisation of the corresponding antenna element (12) is non-linear, and having a first axis (A1) and a second axis (A2) orthogonal to the first axis. Each of the first and second axes (A1; A2) has a length in the range of about 0.05-0.2 times the operating wavelength of the incoming radio wave (52) and the ratio of the length of the first axis A1 to the length of the second axis A2 is between about 1-2.5. There is also a method of configuring an antenna array 10 for detecting an incoming radio wave (52), and a method of determining the angle of arrival of a radio wave (52) impinging on such an antenna array (10).