Active Antenna Calibration Across Multiple PCBs
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Solution Overview
Problem
Current methods fail to accurately calibrate transceivers disposed on different printed circuit boards within active antennas, which is essential for digital beam-forming applications, due to limitations in fabrication and processing techniques.
Innovation Solution
The proposed solution involves an active antenna system with multiple transceiver unit arrays, multiplexers, calibrators, and a feature difference calculating unit that transmit calibration signals through RF connections and perform feature compensation in the digital domain to achieve accurate calibration across boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If transceiver arrays are disposed on multiple PCBs to accommodate the maximum number of transceivers, then the quantity of transceivers is improved, but the calibration accuracy deteriorates due to scattered features across different boards
Solution Approach 1:
A calibration signal is introduced as an intermediary to transfer calibration information across multiple PCBs. The calibration signal passes through transceiver arrays on different boards, enabling feature comparison and calibration without requiring direct physical connection between boards. This mediator approach resolves the calibration accuracy issue while maintaining the ability to dispose transceivers on multiple PCBs.
Solution Approach 2:
The system implements feedback by measuring features of calibration signals received from other PCBs and using these measurements to adjust and compensate for feature scattering. Each transceiver array receives calibration signals from arrays on other boards, measures their features, and uses this feedback information to achieve accurate calibration across all boards simultaneously.
2Quantity of substance
If the PCB length is extended beyond fabrication limits, then more transceiver arrays can be arranged, but the manufacturing precision deteriorates due to fabrication and processing technique limitations
Solution Approach 1:
The transceiver array system is segmented across multiple separate PCBs, each within acceptable fabrication length limits. Instead of creating one long PCB that would exceed manufacturing capabilities, the system divides the total number of transceiver arrays into groups distributed across multiple shorter PCBs, maintaining manufacturing precision while achieving the desired quantity.
Solution Approach 2:
The system transitions from a single-dimension linear arrangement on one PCB to a multi-dimensional configuration across multiple PCBs. By utilizing the spatial dimension of board arrangement and implementing inter-board calibration signals, the system achieves equivalent functionality to a single long PCB while adhering to fabrication constraints.
3Device complexity
If transceiver arrays are distributed across multiple boards, then the device complexity is reduced for individual boards, but the calibration difficulty increases due to scattered features across boards
Solution Approach 1:
The calibration signal serves multiple functions simultaneously: it acts as a test signal for measuring features, as a reference for calibration, and as a communication medium between different PCBs. This multi-functional approach simplifies the overall calibration process despite the distributed configuration, as the same signal mechanism handles multiple calibration tasks across all boards.
Data Source
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AI summary
A calibration method and an active antenna are provided. The active antenna includes K antenna dipole arrays, 1st to Kth transceiver unit arrays corresponding to the antenna dipole arrays, 1st to Kth calibrators, a feature difference calculating unit, and baseband processing modules. The 1st to Kth calibrators are configured to obtain P feature difference values between P calibration signals passing through all calibration loops of the active antenna and an original calibration signal. The feature difference calculating unit is configured to calculate a feature difference value of a receiving channel and/or transmitting channel of each transceiver unit relative to a reference receiving channel and/or transmitting channel respectively. Each baseband processing module is configured to perform feature compensation on a service signal of the corresponding transceiver unit in a digital domain. Therefore, feature differences between all transceivers respectively disposed on a plurality of boards of the transceiver arrays can be calculated, so as to realize accurate calibration on transceiver arrays when the transceiver arrays are distributed on a plurality of boards.