Phase Adjusting Circuit for Millimeter Wave Radar Beamforming
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Solution Overview
Problem
Existing phase adjustment circuits for high-frequency signals, such as those used in vehicle-mounted millimeter wave radars, face challenges in achieving high accuracy due to phase errors influenced by temperature and antenna arrangement, particularly in beamforming applications where precise control of phase differences is required to maintain beam direction accuracy.
Innovation Solution
A phase adjusting circuit and method that introduce a time difference between two signal paths, utilizing a phase shifter and phase difference detection circuit to adjust the phase difference to a target value, allowing for improved accuracy without increasing circuit complexity or size, by generating a reference signal and adjusting its frequency and phase based on detected phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phase shifter is used to dynamically change the phase amount, then the emission direction can be dynamically switched, but the phase control accuracy deteriorates at high frequencies (several tens GHz)
Solution Approach 1:
The patent implements a feedback mechanism where the phase difference detection circuit continuously monitors the actual phase difference between signals from multiple antennas, and the adjusting signal generation circuit dynamically adjusts the phase shifter control signals to minimize the detected phase error. This closed-loop feedback system compensates for frequency-dependent phase errors and maintains accurate beam direction control at high frequencies.
Solution Approach 2:
The patent replaces direct mechanical/high-frequency phase control with an indirect control method using signal processing. Instead of directly controlling high-frequency phase with hardware components that have limited accuracy, the system uses lower-frequency adjusting signals generated by the adjusting signal generation circuit to control phase shifters, with continuous correction based on phase difference detection feedback.
2Measurement precision
If phase error correction is performed considering temperature and other factors, then the phase accuracy can be improved, but the correction process becomes very complicated
Solution Approach 1:
The patent implements a self-calibrating system where the phase adjustment circuit automatically detects and corrects its own phase errors without requiring external calibration data or complex pre-programmed correction tables. The phase difference detection circuit continuously monitors actual phase differences, and the adjusting signal generation circuit autonomously generates correction signals, making the system self-correcting and adaptive to environmental changes like temperature.
Solution Approach 2:
The patent dynamically changes the control parameters (phase shift amounts) based on real-time feedback from the phase difference detection circuit. Instead of using fixed correction values for different temperatures, the system continuously adjusts phase parameters to minimize detected phase errors, adapting to temperature and other environmental factors through parameter optimization rather than complex pre-correction.
3Adaptability or versatility
If the emission direction is corrected by changing the chassis angle, then the beam direction can be maintained horizontal, but the phase adjustment accuracy requirement increases to several degrees
Solution Approach 1:
The patent uses feedback from the phase difference detection circuit to continuously monitor and correct phase relationships after chassis angle changes. When the chassis angle changes, the feedback mechanism detects the resulting phase deviations and the adjusting signal generation circuit generates correction signals to maintain the desired beam direction, achieving high accuracy without requiring manual re-adjustment.
Solution Approach 2:
The patent performs preliminary phase adjustment by the adjusting signal generation circuit before beam transmission, based on detected phase differences. This preliminary correction of phase relationships ensures that even after chassis angle changes, the phase accuracy is maintained at the required several-degree level without requiring complex mechanical re-alignment.
4Measurement precision
If a phase difference detection circuit is used to control phase to an arbitrary value, then high accuracy can be achieved, but the circuit complexity increases
Solution Approach 1:
The patent merges the phase difference detection function with the existing beamforming signal paths. The phase difference detection circuit utilizes signals already present in the system (transmission signals from multiple antennas) and combines them to detect phase differences, rather than requiring separate dedicated detection paths. This integration approach achieves high accuracy while minimizing additional circuit complexity.
Solution Approach 2:
The adjusting signal generation circuit serves multiple functions: it generates control signals for phase shifters, processes feedback from the phase difference detection circuit, and dynamically adjusts phase relationships. This multi-functional design achieves arbitrary phase control accuracy without requiring separate dedicated circuits for each function, reducing overall system complexity.
Data Source
AI summary
A phase adjusting circuit is provided, including a signal generation circuit receiving a frequency adjusting signal and generating a reference signal having a frequency corresponding to the frequency adjusting signal; a first path receiving the reference signal and providing a first signal; a second path receiving the reference signal and providing a second signal, and time for the reference signal passing through the second path is different from time for the reference passing through the first path; a phase shifter disposed on the first path or the second path and shifting a phase of the reference signal based on a phase adjusting signal; a phase difference detection circuit detecting a phase difference between the first and the second signals; and an adjusting signal generation circuit generating the frequency adjusting signal and the phase adjusting signal based on the phase difference so that the phase difference becomes a target value.