Multiport Amplifier Calibration for Phase Drift and Signal Leakage
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Solution Overview
Problem
Multiport Amplifiers (MPAs) in High Throughput Satellite (HTS) applications face performance degradation due to gain and phase variations over time, leading to signal leakage and interference across channels, particularly at higher frequency bands like Ku and Ka, where relative phase variations can be as large as 20 degrees and gain variations can be up to 2 dB over 15 years.
Innovation Solution
A calibration method is implemented that uses a pilot signal to detect and measure phase and amplitude changes in MPA components, such as Travelling Wave Tube Amplifiers (TWTAs), allowing for adjustments to be made to maintain optimal phase and amplitude relationships, with shared calibration hardware and on-board adjustment systems to minimize power leakage and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MPA components operate over long periods at high frequency bands, then signal amplification capability is maintained, but phase and gain variations cause power leakage and interference
Solution Approach 1:
The system performs preliminary calibration by injecting a pilot signal and measuring the transfer function to determine phase and gain variations before they cause significant power leakage. This advance measurement allows the system to proactively adjust amplifier weights to compensate for drift, preventing harmful interference rather than reacting to it after occurrence
Solution Approach 2:
The system continuously monitors phase and gain variations by comparing the measured transfer function against reference values. This feedback mechanism enables real-time detection of component drift and triggers automatic recalibration of amplifier weights, creating a closed-loop control system that maintains performance while minimizing power leakage over time
2Measurement precision
If calibration hardware is dedicated to each MPA, then calibration precision is improved, but system complexity and cost increase
Solution Approach 1:
The calibration system uses a universal approach where a single set of calibration components can service multiple MPAs. The pilot signal injection and transfer function measurement methodology is applicable across different MPA configurations, and calibration data from one MPA can inform adjustments for others, reducing the need for completely dedicated hardware for each amplifier while maintaining adequate calibration precision
Solution Approach 2:
The system creates a digital model of the MPA's transfer function by measuring and storing phase and gain characteristics. This copied representation allows the system to simulate and analyze amplifier behavior without requiring physical test equipment for every measurement, reducing hardware complexity while preserving measurement capability through mathematical modeling
Data Source
AI summary
An amplifier system includes an input network having a plurality of input ports; an output network having a plurality of output ports; a plurality of amplification units coupled between the input network and the output network, the plurality of amplification units configured to amplify signals from the plurality of input ports; and a calibration unit coupled between the plurality of amplification units and the output network to calibrate amplified signals from the plurality of amplification units.