Phased Array Transceiver Feedback Paths for RF Calibration
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Solution Overview
Problem
Current RF transceiver systems face challenges in calibrating phase and amplitude adjustments across multiple antenna elements, particularly in mass production environments where component tolerances are wider and millimeter-wave signals are involved, leading to performance variations and increased physical size due to built-in test circuits that introduce undesired couplings.
Innovation Solution
The implementation of switchable transmit and receive RF processing paths with switchable feedback paths and RF combiners allows for calibration and linearization of RF paths by coupling phase and amplitude adjusted signals through RF combiners to obtain combined signals for calibration and linearization, reducing the need for extensive feedback paths and test circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If built-in test circuits are added for calibration, then calibration capability is improved, but physical size increases and undesired couplings are introduced
Solution Approach 1:
The patent makes existing RF processing paths serve dual purposes: normal signal transmission and calibration functions. By configuring existing transmit and receive paths to also function as calibration paths, the system achieves calibration capability without adding dedicated test circuits, thereby avoiding increased physical size and undesired couplings
Solution Approach 2:
The transceiver system performs calibration using its own existing RF processing paths rather than requiring external test equipment. The system calibrates itself by utilizing its internal transmit and receive paths to generate and measure calibration signals, eliminating the need for separate built-in test circuits
2Reliability
If separate feedback paths are added for each transmit path, then linearization capability is improved, but device complexity and couplings increase
Solution Approach 1:
The patent configures existing receive paths to serve dual purposes: normal signal reception and feedback for linearization. By making receive paths universally functional, the system obtains feedback signals for digital pre-distortion without requiring separate feedback paths for each transmit path, thereby reducing device complexity and couplings
Solution Approach 2:
The patent merges the feedback function with the existing receive paths. Instead of creating separate feedback paths, the system combines the linearization feedback function with the normal receive function, allowing the same hardware to perform both tasks through appropriate switching and configuration
3Measurement precision
If more RF paths are calibrated, then performance accuracy is improved, but calibration complexity increases
Solution Approach 1:
The patent performs calibration of multiple RF paths by systematically selecting one path as reference and sequentially calibrating other paths against it. This preliminary establishment of a reference path simplifies the overall calibration process, making it more manageable despite calibrating multiple paths for high accuracy
Solution Approach 2:
The patent divides the calibration process into manageable segments by calibrating paths sequentially rather than simultaneously. Each path is calibrated independently against a reference, breaking down the complex multi-path calibration into simpler individual calibration tasks that can be performed systematically
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 simplifies the calibration and linearization process, reducing the physical size of transceivers, minimizing couplings, and improving performance by enabling accurate phase and amplitude adjustments across multiple antenna elements, while maintaining high power output efficiency.
Implementation Method 1
couple a portion of a phase and amplitude adjusted RF signal through each of an arbitrarily selected reference transmit path and a target transmit path to one or more RF combiners to obtain a combined RF signal
Data Source
AI summary
Methods and devices for streamlining phase and amplitude calibration and linearization in RF transceiver circuits including a plurality of switchable transmit and receive processing paths is presented. According to one aspect, switchable feedback paths are provided that can selectively feedback a portion of a transmitted RF signal or a test RF signal for use in the calibration. According to another aspect, the switchable feedback paths include combination of switches and couplers to selectively combine feedback from one or more of the switchable feedback paths. According to another aspect, the switchable feedback paths reuse portions of the receive paths of the plurality of switchable transmit and receive processing paths. The switchable feedback paths can be used to provide a combined feedback RF signal based on one or more transmitted RF signals that can be used as a digital pre-distortion feedback for linearization of the one or more transmitted RF signals.