Phased Array Antenna Calibration via Sub-Array Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional calibration methods for phased array antennas, such as the REV method, face challenges in determining the phase of antenna elements when the interval between elements is narrow, leading to increased measurement time and difficulty in distinguishing electric field radiation from each element.
Innovation Solution
A calibration system that includes a probe antenna, amplitude phase measurement unit, back projection processing unit, and antenna control unit to measure and calculate amplitude and phase distributions on the electromagnetic radiation surface, allowing for phase determination even with narrow element intervals, using multiple probes and phase difference calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the REV method is used to determine amplitude and phase of each antenna element, then the relative phase can be determined by measuring only amplitude, but the calibration time increases enormously as the number of antenna elements increases
Solution Approach 1:
The patent divides the array antenna into multiple sub-arrays, where each sub-array contains a subset of antenna elements. By measuring each sub-array separately and combining the results, the calibration process avoids the exponential time increase associated with measuring all elements simultaneously, thus reducing overall calibration time while maintaining phase determination accuracy.
Solution Approach 2:
The patent measures only a portion of the antenna elements at a time rather than all elements. By selectively measuring subsets of elements in multiple stages and combining the measurements, the system achieves complete calibration with reduced measurement time compared to measuring all elements in a single exhaustive process.
2Productivity
If back projection method is used to estimate aperture plane distribution, then relative phase of all antenna elements can be measured at once, but it becomes difficult to separately distinguish electric field radiation from each element when interval between elements is not sufficiently large
Solution Approach 1:
The patent segments the antenna array into multiple sub-arrays with sufficient spacing between them. This segmentation allows the back projection method to effectively distinguish the electric field radiation from each sub-array even when the overall element interval is small, thereby maintaining phase determination accuracy while achieving efficient simultaneous measurement of all elements.
Solution Approach 2:
The patent applies different measurement or processing characteristics to different sub-arrays or regions of the antenna array. By treating each sub-array as a distinct entity with its own measurement characteristics, the system can resolve the interference issue caused by narrow element intervals while maintaining high measurement efficiency through parallel processing.
3Area of stationary object
If narrow interval between antenna elements is used, then the antenna size is reduced, but the ability to separately distinguish electric field radiation from each element deteriorates
Solution Approach 1:
The patent divides the compact antenna array into multiple sub-arrays, allowing the system to maintain a small overall aperture while enabling distinct measurement of each sub-array's radiation characteristics. This segmentation approach preserves the compact size advantage while overcoming the measurement difficulty caused by narrow element intervals.
Solution Approach 2:
The patent introduces sub-array grouping as an intermediary structure between individual antenna elements and the measurement system. This intermediary organization allows the measurement system to distinguish between closely spaced elements by treating groups of elements as distinct radiation sources, thereby enabling accurate measurement despite the narrow overall interval.
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 efficient measurement and calibration of amplitude and phase on the electromagnetic radiation surface of phased array antennas, even when element intervals are narrow, reducing measurement time and improving calibration accuracy.
Implementation Method 1
a probe antenna that receives a radio signal at a plurality of measurement positions set on a predetermined measurement plane in a near field area of a measured antenna
Data Source
AI summary
To provide a calibration system and a calibration method capable of measuring the amplitude and the phase of the radio signal on the electromagnetic radiation surface of the measured antenna, even in the case where the interval between antenna elements is narrow. The calibration system 1 includes: an antenna control unit 16 that selects and excites a combination of antenna elements from among a plurality of antenna elements provided in the measured antenna 100 and thereafter selects and excites another combination of antenna elements; and a probe antenna 12 that receives an electromagnetic wave of the radio signal transmitted from the combination of the antenna elements at a plurality of measurement positions set within a predetermined measurement plane P of the near field area of the measured antenna 100, each time a combination of the antenna elements selected by the antenna control unit 16 are switched.