Dual Linear Antenna Calibration for Circular Polarization Links
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Solution Overview
Problem
Mobile terminals with linearly polarized antennas are unable to efficiently transmit and receive circularly polarized signals, leading to interference and reduced frequency efficiency in satellite communication systems.
Innovation Solution
A method and apparatus that utilize horizontally and vertically polarized antennas to receive and transmit circularly polarized signals by generating and processing baseband signal vectors, estimating receiving polarization vectors through eigenvectors and channel estimations, and calibrating power amplifiers and local oscillator signals to minimize polarization loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If mobile terminals use linearly polarized antennas, then the device complexity is reduced and ease of manufacture is improved, but the ability to transmit and receive circularly polarized signals deteriorates, causing interference and reduced frequency efficiency
Solution Approach 1:
The patent divides the linearly polarized antenna system into two separate linearly polarized antennas (first and second antennas with orthogonal polarizations) that work together to transmit and receive circularly polarized signals. By segmenting the function across multiple simple antennas rather than using a single complex circularly polarized antenna, the system achieves circular polarization capability while maintaining simplicity of individual antenna elements.
2Ease of manufacture
If mobile terminals use linearly polarized antennas, then the ease of manufacture is improved, but signal quality and polarization matching deteriorate, leading to polarization loss
Solution Approach 1:
The patent combines the signals from two linearly polarized antennas (with orthogonal polarizations) to form circularly polarized signals. By merging the functionality of multiple simple antennas, the system achieves the signal quality and polarization characteristics of a circularly polarized antenna while maintaining the manufacturing simplicity of linearly polarized elements.
Solution Approach 2:
The patent creates a composite antenna system where two linearly polarized antennas work together as a unified structure. This composite approach combines the advantages of simple linearly polarized elements with the performance benefits of circular polarization, achieving both ease of manufacture and high signal quality.
3Productivity
If satellites switch between RHCP and LHCP for adjacent beams, then frequency efficiency is improved and interference is reduced, but the requirement for circularly polarized transmission deteriorates the compatibility with mobile terminals using linearly polarized antennas
Solution Approach 1:
The patent makes the mobile terminal universally compatible with both linearly and circularly polarized satellite signals. By equipping the terminal with two linearly polarized antennas that can process both polarization types, the device gains multi-functionality - it can communicate with satellites using traditional linear polarization or advanced circular polarization schemes, thereby maintaining compatibility while enabling access to frequency-efficient circularly polarized communication.
Data Source
AI summary
Aspects of the disclosure provide an apparatus for transmitting a circularly polarized signal by linearly polarized antennas. Processing circuitry of the apparatus generates a transmitted baseband signal vector. Based on the transmitted baseband signal vector, power amplifiers (PAs) of the apparatus generates transmitted radio frequency (RF) signals. The transmitted RF signals are received by receiving circuitry of the apparatus to obtain a received baseband signal vector. A controller of the apparatus calibrates the PAs and local oscillator (LO) signals of frequency converters of the apparatus based on the received baseband signal vector. A horizontally polarized antenna and a vertically polarized antenna of the apparatus transmit a circularly polarized signal based on the calibrated PAs and the calibrated LO signals.