In-situ Phase Calibration for FMCW Radar Rx Channels
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Solution Overview
Problem
Conventional calibration methods for radio frequency integrated circuits (RFICs) in millimeter-wave radar systems are costly, time-consuming, and not suitable for in-field calibration, making it difficult to accurately characterize frequency responses and compensate for variations such as temperature changes and component aging.
Innovation Solution
A method for calibrating frequency-modulated continuous-wave (FMCW) radar systems with multiple receiving channels involves using a programmable phase shifter and analog-to-digital converter (ADC) to generate phase response curves by sweeping the phase shifter control word across a range of values, forming amplitude curves, and performing curve fitting to determine the phase response of each channel, allowing for in-situ calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional calibration methods are used for RFICs, then manufacturing precision may be improved, but cost and time consumption increase significantly
Solution Approach 1:
The radar system performs self-calibration using its own internal resources (transmitter, receiver channels, and signal processing capabilities). The system generates calibration signals internally and processes them through the receiving channels to automatically determine phase responses without requiring external calibration equipment or facilities, thereby reducing calibration time and cost while maintaining accuracy.
Solution Approach 2:
The calibration method uses the radar system's existing transmitting and receiving components for dual purposes: normal radar operation and calibration measurements. The same transmitter generates both operational signals and calibration chirp signals, and the same receiver channels process both target returns and calibration signals, eliminating the need for separate calibration equipment.
2Manufacturing precision
If conventional calibration methods are used for RFICs, then manufacturing precision may be improved, but device complexity and cost increase
Solution Approach 1:
The calibration method uses the radar system's existing transmitting and receiving components for dual purposes: normal radar operation and calibration measurements. The same transmitter generates both operational signals and calibration chirp signals, and the same receiver channels process both target returns and calibration signals, eliminating the need for separate calibration equipment.
Solution Approach 2:
The radar system performs self-calibration using its own internal resources (transmitter, receiver channels, and signal processing capabilities). The system generates calibration signals internally and processes them through the receiving channels to automatically determine phase responses without requiring external calibration equipment or facilities, thereby reducing calibration system complexity and cost.
3Manufacturing precision
If conventional calibration methods are used for RFICs, then manufacturing precision may be improved, but adaptability to field conditions decreases
Solution Approach 1:
The radar system performs self-calibration using its own internal resources (transmitter, receiver channels, and signal processing capabilities). The system generates calibration signals internally and processes them through the receiving channels to automatically determine phase responses without requiring external calibration equipment or facilities, thereby reducing calibration system complexity and cost.
Solution Approach 2:
The calibration system is designed to be dynamically adaptable to different operating conditions. The phase response curves can be measured and updated under various temperature and environmental conditions, allowing the system to compensate for drift and aging effects that occur during field operation, thus maintaining accuracy throughout the radar's operational life.
4Manufacturing precision
If conventional calibration methods are used for RFICs, then manufacturing precision may be improved, but productivity decreases
Solution Approach 1:
The radar system performs self-calibration using its own internal resources (transmitter, receiver channels, and signal processing capabilities). The system generates calibration signals internally and processes them through the receiving channels to automatically determine phase responses without requiring external calibration equipment or facilities, thereby reducing calibration system complexity and cost.
Solution Approach 2:
The calibration data (phase response curves) can be pre-measured and stored in memory during manufacturing or initial setup. During normal operation, the system retrieves and applies these pre-characterized phase responses rather than performing real-time calibration measurements, significantly improving operational productivity while maintaining accuracy.
Data Source
AI summary
A method for calibrating a receiving (Rx) channel of a frequency-modulated continuous-wave (FMCW) radar system includes: setting the Rx channel in calibration mode, where the Rx channel includes a mixer, a phase shifter coupled to a first input of the mixer, a filter coupled to an output of the mixer, and an analog-to-digital converter (ADC) coupled to an output of the filter; setting a value for a phase shifter control word of the phase shifter; sending a chirp signal to the phase shifter; sending a modulated chirp signal to a second input of the mixer, where an output signal at the output of the mixer includes a beat signal; and forming an amplitude curve based on data samples from the ADC, where the amplitude curve illustrates amplitudes of the beat signal at a plurality of frequencies within an operating frequency band of the FMCW radar system.