Antenna Array Calibration via Mutual Coupling Monitoring
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Solution Overview
Problem
Existing antenna array calibration techniques require specialized equipment and dedicated calibration processes, which are not compatible with continuous communication operations, leading to communication delays and inefficiencies due to phase and gain mismatches in phase shifters and amplifiers.
Innovation Solution
A method and apparatus for calibrating antenna arrays by operating a limited number of elements to transmit and monitor signals, using mutual coupling to determine calibration coefficients for phase and gain errors, allowing for concurrent calibration and communication without dedicated calibration time, using a controller, local signal monitor, and calibrator to adjust phase shifters and amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated calibration process is used, then calibration accuracy is improved, but communication operations are interrupted causing delays
Solution Approach 1:
The patent merges the calibration function with ongoing communication operations by having antenna elements perform both calibration measurements and data transmission/reception simultaneously. The calibration signals are embedded within the communication signal stream, allowing both functions to coexist without interruption.
Solution Approach 2:
The calibration process operates continuously alongside communication operations rather than being performed periodically or separately. Antenna elements continuously monitor calibration signals while maintaining normal communication functions, ensuring uninterrupted service and real-time calibration updates.
2Measurement precision
If specialized calibration equipment is used, then calibration precision is improved, but device complexity increases
Solution Approach 1:
The antenna array performs self-calibration using its own antenna elements as both transmitters and receivers. Each antenna element transmits calibration signals that are monitored by other elements in the array, eliminating the need for external calibration equipment and reducing system complexity.
Solution Approach 2:
The antenna elements serve multiple functions: they perform both calibration measurements and normal communication operations. The same hardware components used for data transmission are also used for calibration, eliminating dedicated calibration equipment and reducing overall system complexity.
3Measurement precision
If all antenna elements are used for calibration, then calibration completeness is improved, but communication throughput decreases
Solution Approach 1:
Calibration and communication operations occur simultaneously and continuously rather than sequentially. While some antenna elements perform calibration measurements, others maintain communication functions, and all elements continuously update their calibration status without interrupting overall system productivity.
Solution Approach 2:
The antenna array is segmented into different functional groups during calibration: some elements transmit calibration signals, others receive and monitor them, while remaining elements maintain communication operations. This segmentation allows calibration to be performed on subsets of elements without affecting overall communication throughput.
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 online calibration of antenna arrays during communication operations, reducing delays and maintaining beamforming performance by correcting phase and gain errors, thus improving the efficiency and reliability of point-to-multipoint communication systems.
Implementation Method 1
determining a calibration coefficient for correcting phase and gain errors introduced in a transmission and/or reception path of the antenna array based on properties of mutual couplings between pairs of antenna elements
Data Source
AI summary
Methods and apparatus for calibrating an antenna array are provided. A limited number of antenna elements of the array are operated to broadcast a signal. The signal carries information relevant to operation of a communication network, for receipt by other devices. By using one or a limited number of antenna elements, a radiation pattern covering a wide area is achieved. Concurrently, transmission of the broadcast signal is monitored using another one or more antenna elements of the array, operating in a receive mode. The monitored signal is used in an antenna array calibration operation. The procedure is repeated for various different transmitting and receiving antenna elements, resulting in a sequence of broadcasts using different parts of the array. The calibration results can be used to correct for operating errors such as phase shifter errors. The corrected phase shifters can then be used for beamforming during another phase of communication.