Phased Array Calibration via Parasitic Coupling
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Solution Overview
Problem
Phased array antenna systems face challenges in calibrating phase and amplitude weights due to mismatches in transmission lines, requiring efficient methods to compensate for initial and environmental errors for optimal beamforming performance.
Innovation Solution
A calibration method using built-in-test equipment (BITE) that injects tones through parasitic coupling between antenna elements, measures phase differences, and populates a lookup table to adjust phase shifters, enabling accurate calibration of phase and amplitude errors across the phased array system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional over-the-air calibration methods are used, then phase and amplitude weights can be calibrated, but the system requires complex external equipment and procedures
Solution Approach 1:
The patent implements self-service calibration by utilizing the phased array system's own antenna elements and parasitic coupling mechanisms to perform calibration without external equipment. The system uses its received signal strength indicator (RSSI) measurements and phase difference calculations between antenna elements to automatically determine and apply calibration weights, making the calibration process self-contained and eliminating complex external calibration equipment
Solution Approach 2:
The patent introduces parasitic coupling as an intermediary mechanism to transfer calibration signals between antenna elements. By utilizing the natural parasitic coupling between adjacent antenna elements, the system can measure phase differences and propagate calibration information across the array without requiring direct physical connections or complex external test equipment
2Ease of manufacture
If parasitic coupling is used for calibration, then calibration can be performed using built-in-test equipment, but phase difference measurements are required between antenna elements
Solution Approach 1:
The patent employs feedback mechanisms where the system measures phase differences between antenna elements using parasitic coupling, stores these measurements in lookup tables, and uses them to adjust phase shifters in real-time. The continuous measurement and adjustment loop enables automatic compensation for phase and amplitude variations, making the calibration process adaptive and self-correcting
Solution Approach 2:
The patent performs preliminary calibration measurements by injecting test tones through parasitic coupling and measuring phase differences between antenna elements before actual operation. These preliminary measurements populate lookup tables that contain pre-calculated phase correction values, enabling rapid calibration without requiring complex real-time measurements during operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively calibrates the phased array system, reducing errors and ensuring accurate beamforming by compensating for phase and amplitude mismatches, and can be performed without the need for complex over-the-air calibration, enhancing system performance and reliability.
Implementation Method 1
receiving the tone by a second antenna element of the antenna array of the phased array system through parasitic coupling between the first antenna element and the second antenna element
Data Source
AI summary
A calibration method for a phased array system comprises sequentially injecting a tone into a first plurality of antenna elements of an antenna array, receiving the tone by a second plurality of antenna elements of the antenna array through parasitic coupling between the first plurality of antenna elements and the second plurality of antenna elements, measuring a plurality of phase errors between the first plurality of antenna elements and the second plurality of antenna elements, populating a lookup table with the plurality of phase errors, and calibrating a plurality of phase shifters associated with a plurality of channels in the phased array system using the plurality of phase errors in the lookup table.