Phased Array Calibration Using Virtual Near-Field Probes
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Solution Overview
Problem
Calibration of large phased array antennas is costly and inefficient due to reliance on expensive near and far field sensors, which require significant equipment and downtime, and existing methods lack direct detection of component degradation and vector state errors.
Innovation Solution
A calibration system using a movable calibrator with a support structure and a calibration module to compute voltage sums at different positions, allowing for precise alignment and adjustment of array elements without the need for extensive sensor equipment, enabling accurate calibration of large arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If near field or far field sensing methods are used for calibration, then calibration accuracy can be achieved, but equipment cost and system complexity increase significantly
Solution Approach 1:
The patent uses a digital model (virtual near-field probe) to replicate the function of a physical near-field probe. The digital model processes received signal strength indicators (RSSI) from wireless devices to determine aperture vector states, eliminating the need for expensive physical sensing equipment while maintaining calibration accuracy.
Solution Approach 2:
The patent replaces the mechanical/physical near-field probe sensing system with a computational approach using wireless signal measurements and digital signal processing. The physical probe and its positioning mechanisms are substituted with a digital model that processes electromagnetic signal data.
2Measurement precision
If near field sensors are used for calibration, then aperture vector state can be detected, but system downtime increases due to positioning requirements
Solution Approach 1:
The digital model replicates the near-field probe functionality without requiring physical positioning operations. Wireless devices transmit signals that are processed by the digital model to determine aperture vector states, eliminating the time-consuming mechanical positioning of physical probes.
Solution Approach 2:
The calibration process can occur while the antenna system remains operational, as wireless devices can transmit calibration signals without requiring the antenna to be taken offline for physical probe positioning and measurement.
3Measurement precision
If far field sensors are used for large arrays, then calibration can be performed, but separation distance requirements make the approach complex and expensive
Solution Approach 1:
The digital model creates a virtual near-field probe that eliminates the need for physical far-field sensing arrangements. By processing wireless signal measurements through the digital model, the system achieves calibration capability without requiring large separation distances between sensors and the antenna aperture.
4Manufacturing precision
If individual components are calibrated in the beam formation chain, then initial calibration can be achieved, but verification of calibration state becomes difficult
Solution Approach 1:
The system uses wireless devices to transmit calibration signals and the base station processes these signals through the digital model to determine aperture vector states. This creates a feedback loop that verifies the calibration state of the antenna system by measuring actual signal characteristics and comparing them against expected values.
Data Source
AI summary
Methods and apparatus for a calibration system including a support structure movable over an array, a super-element secured to the support structure to obtain information at selected locations in relation to the array, and a processor to compute a sum of voltages for determining a level of calibration for the array.