Circular Polarization Antenna Axial Ratio Correction Under Mutual Coupling
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Solution Overview
Problem
Conventional circular polarization antenna devices face challenges in determining a correction control amount to improve the axial ratio due to mutual coupling between antenna elements, leading to changes in emission patterns and reduced communication quality or power transmission efficiency.
Innovation Solution
A circular polarization antenna device with a configuration that includes multiple antennas, each with orthogonal feeding terminals, amplitude and phase shifters, and processing circuitry to calculate and control correction amounts based on emission pattern shapes and coupling amounts, adjusting amplitude and phase to optimize axial ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circular polarization antenna devices are used with orthogonal feeding terminals, then circular polarization performance is achieved, but mutual coupling between adjacent antenna elements causes emission pattern changes and axial ratio deterioration
Solution Approach 1:
The patent calculates and stores coupling amounts between feeding terminals in advance through electromagnetic field analysis or measurement. These pre-calculated coupling amounts are then used to determine correction control amounts, allowing the system to compensate for mutual coupling effects without requiring real-time complex calculations or physical modifications to the antenna structure.
Solution Approach 2:
The patent introduces correction control amounts that modify the amplitude and phase parameters of signals fed to adjacent antenna elements. By changing these parameters based on pre-calculated coupling amounts, the system compensates for mutual coupling effects and maintains consistent axial ratio performance across different scanning angles.
2Area of stationary object
If beam scanning is performed in wide angle direction, then coverage area is increased, but cross polarization component increases and axial ratio deteriorates
Solution Approach 1:
The patent employs a feedback mechanism where the correction control amounts, calculated based on pre-stored coupling amounts and emission pattern functions, are applied to adjust the feeding signals. This feedback loop compensates for the degradation caused by wide-angle scanning, maintaining axial ratio performance across the entire scanning range.
3Device complexity
If two-point feeding patch antenna is used instead of dipole antennas, then integration is improved, but mutual coupling between feeding points becomes significant causing emission pattern changes
Solution Approach 1:
The patent pre-calculates the coupling amounts between the two feeding points of the patch antenna through electromagnetic field analysis or measurement. These coupling amounts are stored in advance and used to determine the correction control amounts, allowing the system to compensate for the significant mutual coupling effects without requiring physical separation of the feeding points.
Data Source
AI summary
A circular polarization antenna device includes: a correction control amount calculating unit that calculates a correction control amount for axial ratio correction on the basis of a function representing a shape of an emission pattern of a high-frequency signal emitted from an antenna element and a coupling amount between a first feeding terminal and a second feeding terminal; an amplitude adjustment controlling unit that controls amplitude adjustment performed by a first amplitude adjusting circuit and a second amplitude adjusting circuit on the basis of the correction control amount; and a phase shifter controlling unit that controls phase adjustment performed by a first phase shifter and a second phase shifter on the basis of the correction control amount.