Phased Array Antenna Phase Calibration via Symmetric Segmentation
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Solution Overview
Problem
Existing phased array antennas face challenges in accurately calibrating the phase of antenna elements to reduce side lobes, particularly due to low detectable power changes and shallow null points in directivity patterns caused by differing radio wave power outputs among elements.
Innovation Solution
A phased array antenna system with an oscillator, antenna elements, phase shifters, a distributor, and a control processor that performs calibration processes to align phases of antenna elements symmetrically arranged around a central axis, using directivity patterns to set phase values and reduce side lobes, even when power outputs differ.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the phased array antenna uses antenna elements with different power outputs to reduce side lobes, then the side lobe reduction is achieved, but the phase calibration precision deteriorates due to shallow null points in directivity patterns
Solution Approach 1:
The calibration process is segmented into two distinct stages: first calibrating antenna elements with equal power outputs to establish a baseline with deep null points, then calibrating antenna elements with different power outputs while referencing the previously calibrated elements. This segmentation allows the system to overcome the shallow null point problem by separating the calibration tasks.
Solution Approach 2:
The patent performs preliminary calibration of antenna elements with equal power outputs before proceeding to calibrate elements with different power outputs. This preliminary action creates a reference framework that enables accurate subsequent calibration despite the power differences, effectively preparing the system in advance to handle the measurement precision challenge.
2Measurement precision
If the phased array antenna calibrates antenna elements with equal power outputs first, then the phase calibration precision is improved, but the device complexity increases due to multi-stage calibration processes
Solution Approach 1:
The patent changes the power output parameter of antenna elements between calibration stages. By systematically varying which elements operate at equal power and which operate at different power levels, the system achieves accurate calibration without requiring complex additional hardware, using parameter changes instead to manage the calibration complexity.
Solution Approach 2:
Antenna elements calibrated in the first stage serve as intermediaries or references for calibrating elements in the second stage. These previously calibrated elements mediate the calibration process, allowing the system to extend accurate phase calibration to elements with different power outputs without directly comparing them against each other, thus simplifying the overall process.
3Ease of operation
If the phased array antenna uses a single-stage calibration process for all antenna elements, then the ease of operation is improved, but the manufacturing precision of the directivity pattern deteriorates
Solution Approach 1:
The calibration operation is segmented into two manageable stages with clear objectives: equal-power calibration followed by differential-power calibration. This segmentation makes the overall complex task more operable by breaking it down into simpler, sequential steps, each with its own optimization goals, thereby maintaining ease of operation while achieving high precision.
Solution Approach 2:
The system performs preliminary calibration of a subset of antenna elements before proceeding to the full calibration. This preliminary action creates a stable reference that simplifies the subsequent calibration operations, making the overall process easier to execute while ensuring high precision in the final directivity pattern.
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
Enables precise phase alignment and reduction of side lobes in the directivity pattern, ensuring a desired directivity pattern is achieved despite varying power outputs from each antenna element.
Implementation Method 1
an oscillator that generates radio waves
Implementation Method 2
a plurality of antenna elements that radiates radio waves
Implementation Method 3
a receiving unit that receives radio waves radiated by the plurality of antenna elements
Data Source
AI summary
A phased array antenna includes an oscillator, a plurality of antenna elements, a phase shifter, a distributor, a receiver, and a control processor. The control processor performs a first calibration process to calibrate a phase of the phase shifter connected to a pair of antenna elements that is selected from the antenna elements and are located at a pair of positions symmetric with respect to a central axis of an array formed by the phased array antenna, and a second calibration process to calibrate a phase of the phase shifter connected to a pair of target antenna elements with respect to a phase of the phase shifter connected to a reference antenna elements located at a central portion of the array. The pair of target antenna elements are located at a pair of positions that are symmetric with respect to the central axis of the array.