Antenna Array Calibration Using Scattering Targets
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Solution Overview
Problem
Current antenna array calibration methods, such as cable-based electronic calibration and antenna-to-antenna calibration, are inefficient and inaccurate, especially for MIMO arrays with multiple antennas, as they do not account for mismatches between antennas and the medium or object under test, and require numerous measurements.
Innovation Solution
A method and system that utilize one or more calibration targets with known electromagnetic scattering properties to measure and analyze reflected RF signals, calculating channel responses and calibration parameters, including electromagnetic, electronic, and leakage responses, to achieve full calibration of the antenna array, regardless of the number of antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cable based electronic calibration is used, then electronic response measurement is achieved, but the method requires separate measurements for each port pair and does not account for antenna-medium mismatch
Solution Approach 1:
The patent introduces calibration targets as intermediary objects with known electromagnetic scattering properties. These targets serve as mediators between the antenna array and the measurement system, enabling simultaneous calibration of multiple antenna ports through a single measurement setup rather than requiring separate cable connections for each port pair.
2Measurement precision
If antenna to antenna calibration is used, then mismatch induced by antennas is considered, but the number of measurements required is double the number of antennas
Solution Approach 1:
The patent merges the calibration process for multiple antenna ports into a single integrated measurement. By using calibration targets with known scattering properties, the system can simultaneously characterize the response of multiple transmit and receive antenna pairs in one measurement session, rather than performing separate measurements for each antenna pair.
Solution Approach 2:
The patent performs preliminary action by placing calibration targets with known electromagnetic scattering properties into the measurement arena before conducting the actual calibration measurements. This preliminary setup enables the system to predict expected channel responses and facilitates faster calibration by eliminating the need for sequential measurements of each antenna pair.
3Measurement precision
If antennas are placed close to one another to prevent reverberations, then measurement accuracy improves, but the medium itself is not taken into account
Solution Approach 1:
The patent changes the approach by not requiring physical relocation of antennas for different measurement conditions. Instead, it uses computational methods to account for medium effects while maintaining fixed antenna positions, thereby adapting the calibration process to different medium conditions without physical reconfiguration.
4Adaptability or versatility
If a large number of antennas are used in the array, then system capability increases, but the calibration process becomes cumbersome and inefficient
Solution Approach 1:
The patent applies universality by designing a calibration method that works for antenna arrays of any size. The same calibration targets and measurement procedure can be used whether the array has a few antennas or many antennas, eliminating the need for different calibration approaches based on array size.
Solution Approach 2:
The patent uses calibration targets with known scattering properties as copies or representations of ideal reference objects. These targets provide predictable electromagnetic responses that can be used to characterize the entire antenna array system without requiring physical access to or measurement of each individual antenna element separately.
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 approach allows for precise calibration of antenna arrays by accounting for antenna and medium behavior, reducing errors and inefficiencies, and improving accuracy, especially for large arrays with many antennas.
Implementation Method 1
transmitting a plurality of RF signals from at least one RF antenna of said plurality of RF antennas towards an arena; obtaining by said antenna array affected multiple RF signals from said arena; measuring the plurality of reflected RF signals
Data Source
AI summary
Systems, device and methods are provided for calibrating an antenna array comprising a plurality of antennas such as a plurality of transmit and receive antennas by utilizing an arena comprising one or more targets and a medium. The methods may comprise transmitting a plurality of Radio Frequency (RF) signals from at least one RF antenna of a plurality of RF antennas towards an arena, obtaining by the antenna array affected multiple RF signals from the arena, measuring the plurality of reflected RF signals by a Radio Frequency Signal Measurement Unit (RFSMU) and calculating a plurality of channel responses from said plurality of affected RF signals, providing by at least one processing unit a first model, which is configured to produce an expected electromagnetic (EM) channel responses of the antenna array and the arena and providing a second model, which comprises a relation between the first model and the antenna array calibration parameters and calculating the array calibration parameters to calibrate the antenna array.