Multiport Amplifier Input Injection for Gain-Phase Calibration
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Solution Overview
Problem
Multiport amplifiers (MPAs) operating at high frequencies, such as Ku and Ka bands, face challenges in maintaining stable phase and amplitude tracking between amplifier units, leading to imperfect port-to-port isolation and signal interference due to long-term performance drift and redundancy switching, necessitating calibration in orbit to correct gain and phase imbalances.
Innovation Solution
A method and apparatus for applying test signals directly between the input network and amplifier units in a multiport amplifier arrangement, allowing for measurement of output signals at any output port and enabling calibration of specific amplifier paths by comparing reference and calibration signal paths, thereby determining gain and phase adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If test signals are injected into MPA INET inputs and monitored at MPA ONET outputs using conventional calibration techniques, then gain and phase adjustments can be determined, but the calibration process becomes complex and requires extensive on-board hardware
Solution Approach 1:
The patent extracts the test signal injection point from the INET input and places it directly at the amplifier input. This removes the need to measure through the entire INET network, simplifying the calibration process and reducing hardware requirements while maintaining measurement accuracy
Solution Approach 2:
The calibration process is segmented into individual amplifier unit calibrations rather than calibrating the entire MPA system at once. By calibrating each amplifier independently with direct test signal injection, the complexity is reduced while maintaining precision
2Reliability
If conventional MPA calibration methods are used with signal injection at INET inputs, then comprehensive system calibration is achieved, but port-to-port isolation remains imperfect due to long-term performance drift
Solution Approach 1:
The patent applies preliminary gain and phase adjustments to each amplifier unit before final system operation. By pre-calibrating individual amplifiers with direct test signal injection and accounting for expected performance drift, the system maintains better port-to-port isolation over time
Solution Approach 2:
The calibration system uses feedback from measured output signals to determine and apply corrective adjustments to each amplifier unit. This closed-loop approach compensates for performance drift and maintains reliable port-to-port isolation
Data Source
AI summary
The invention provides a method and apparatus for applying test signals to a multiport amplifier (MPA) and a method, apparatus and system for determining parameter adjustments for an MPA. Applying test signals to an MPA is performed so as to provide an output signal indicative of parameter adjustments for the MPA, the multiport amplifier arrangement comprising an input network, an amplifier unit and an output network, where the method includes providing a test signal directly to a point in the multiport amplifier arrangement between an output of the input network and an input of the amplifier unit. The method of determining parameter adjustments for a multiport amplifier arrangement includes receiving first and second output signals associated with an output of the multiport amplifier arrangement, the first output signal corresponding to a first signal path through the multiport amplifier arrangement and the second output signal corresponding to a second signal path through the multiport amplifier arrangement and determining parameter adjustments based on the first and second output signals.