Phased Array Antenna Handover Calibration for Beam Accuracy

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Solution Overview

Problem

Existing phased array antennas face challenges in maintaining precise phase and amplitude relationships between signal paths due to degradation of components like LNAs and PAs, necessitating complex calibration circuits that either require system downtime or are overly complex for real-time calibration.

Innovation Solution

A phased array antenna system with control and calibration circuitry that performs field-calibration during handover periods, using a cross-coupled switch to calibrate signal paths without disrupting communication, allowing for simpler circuitry while maintaining beam accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a built-in calibration circuit is implemented to periodically calibrate signal paths in the field, then phase and amplitude relationships can be maintained, but the calibration circuit becomes highly complex

Engineering Contradiction:
Improvephase and amplitude relationship maintenanceVSAvoidcalibration circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes handover periods as periodic opportunities to perform calibration. During these predetermined time intervals when the antenna system is temporarily deactivated for communication with external systems, the calibration circuit activates to adjust phase shifters and amplifier gains. This periodic calibration approach maintains reliability while avoiding the need for continuously complex calibration circuitry that would be required for real-time calibration during active communication.

Inventive Principle:
Principle #19Periodic action

2Reliability

If calibration is performed during predetermined maintenance periods when the antenna system is deactivated, then calibration can be carried out, but communication with satellites or other external systems is interrupted

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcommunication downtime
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs calibration during handover periods, which are predetermined time intervals scheduled in advance when communication with external systems is temporarily suspended. By preparing and executing calibration during these pre-planned maintenance windows, the system ensures accurate calibration without attempting to perform it during active communication when interference would occur.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If current calibration circuits are designed to enable calibration simultaneously with wireless communication, then communication continuity is maintained, but the calibration circuits become highly complex

Engineering Contradiction:
Improvecommunication continuityVSAvoidcalibration circuit complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent employs periodic calibration during handover periods rather than continuous calibration during active communication. This approach allows the calibration circuit to activate only during predetermined intervals when the antenna is temporarily deactivated, significantly reducing circuit complexity compared to systems that attempt simultaneous calibration and communication.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3871291B1System and method for calibrating phased array antennas
Publication Date: 2025.09.03 VIASAT INC
  • EP3871291B1 patent drawingFigure 1A
  • EP3871291B1 patent drawingFigure 1B
  • EP3871291B1 patent drawingFigure 1C

AI summary

An antenna system having an antenna array including at least first and second phased array antennas, and a method for field-calibrating the antenna array. Before and after a handover period, communication with respective first and second external satellites or other communication systems is performed using both the first and second antennas. A first beam is formed prior to the handover period. During a first portion of the handover period: a second beam is formed for the communication with the first satellite using the first antenna; the second antenna is deactivated for external communication; and the second antenna is calibrated. During a second portion of the handover period, the second antenna is reactivated for a handed over communication with the second satellite by forming a third beam using the second antenna, while the first antenna maintains its communication with the first satellite via the second beam.