Transmitter Phase Adjustment for Radar Emission Accuracy
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Solution Overview
Problem
Conventional phase shifters struggle to accurately control the phase of high-frequency transmission waves in the order of several tens of GHz, especially in in-vehicle millimeter wave radar systems, where temperature fluctuations complicate phase correction and require precise adjustments to maintain emission direction accuracy.
Innovation Solution
A transmitter system comprising a phase shifter, a first control circuit to adjust the phase shift amount, a phase difference signal output circuit, an extreme value output circuit, a target value output circuit, and a second control circuit to control the phase shift amount, ensuring the phase difference signal aligns with a target value, thereby achieving precise phase adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional phase shifter is used to control the phase of high-frequency transmission waves, then the device structure is simple, but the phase control accuracy deteriorates with temperature fluctuations and high frequency
Solution Approach 1:
The patent applies preliminary action by measuring and storing the relationship between temperature and phase error in advance through calibration. The calibration process pre-establishes a lookup table that maps temperature values to phase error corrections, which are then applied during operation without requiring real-time complex calculations. This resolves the contradiction by preparing correction data beforehand, enabling high accuracy without adding complex real-time processing hardware.
Solution Approach 2:
The patent replaces complex real-time phase measurement and adjustment mechanisms with a simplified system that uses pre-stored calibration data. Instead of using complex hardware to continuously measure and correct phase errors, the system substitutes this with a lookup table approach combined with temperature sensing, significantly reducing device complexity while maintaining high phase control accuracy through the use of pre-computed correction values.
2Measurement precision
If phase correction is performed in consideration of temperature fluctuations, then phase control accuracy is improved, but the processing complexity increases substantially
Solution Approach 1:
The patent performs phase correction in consideration of temperature by pre-calibrating the system at different temperatures and storing the phase error characteristics in a lookup table. During operation, the system simply queries this pre-prepared table based on the current temperature sensor reading, avoiding complex real-time calculations. This resolves the contradiction by moving the complex processing to the calibration phase rather than the operational phase.
Solution Approach 2:
The system achieves temperature-compensated phase control through self-service by automatically reading the temperature sensor and retrieving the appropriate correction value from the pre-stored lookup table. The calibration data structure is designed to enable automatic selection of correction parameters based on temperature, eliminating the need for complex external processing or manual adjustment while maintaining high accuracy across varying temperatures.
3Measurement precision
If high accuracy phase adjustment is required for emission direction control, then the beam forming performance is improved, but the phase shifter design becomes more complex
Solution Approach 1:
The patent achieves high accuracy emission direction control by pre-calibrating the phase shifter system to account for temperature-dependent phase errors. The calibration process establishes a lookup table that contains pre-computed phase correction values for different temperatures and antenna elements. During operation, the system retrieves these pre-prepared values based on current temperature readings, enabling high precision beam forming without requiring complex real-time phase adjustment mechanisms.
Solution Approach 2:
The patent replaces complex high-precision phase shifter hardware with a simplified approach that uses pre-stored calibration data and temperature-based lookup tables. Instead of designing and manufacturing highly precise phase shifters that can maintain accuracy across temperature variations, the system substitutes this hardware complexity with software-based correction using pre-computed values, achieving the same high emission direction accuracy with simpler hardware.
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 system enables high-accuracy phase control of transmission waves, maintaining emission direction accuracy despite temperature fluctuations and antenna arrangement changes, effectively addressing the limitations of conventional phase shifters in high-frequency applications.
Implementation Method 1
a phase shifter (11) that shifts a phase of an input signal (W) and outputs a shifted signal (WS)
Implementation Method 2
a phase difference signal output circuit (12) that receives the shifted signal (WS) output from the phase shifter (11) and a reference signal (R) and outputs a phase difference signal based on a phase difference between the shifted signal and the reference signal
Data Source
AI summary
The transmitter includes a phase shifter that shifts a phase of an input signal and outputs a shifted signal; a first control circuit changes a phase shift amount of the phase shifter; a phase difference signal output circuit outputs a phase difference signal between the shifted signal and the reference signal; an extreme value output circuit outputs a value of the phase difference signal when the phase difference signal becomes the extreme value; a target value output circuit outputs a target value based on an output from the extreme value output circuit; and a second control circuit controls the phase shift amount of the phase shifter such that a value of the phase difference signal coincides with the target value. The phase shifter outputs, as a transmission wave, the input signal the phase of which is shifted by the phase shift amount controlled by the second control circuit.