Radar Chip Phase Coherence via Frequency-Divided Reference
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Solution Overview
Problem
In radar systems, particularly those using cascaded monolithic microwave integrated circuits (MMICs), accurately measuring the phases of RF signals at Extremely High Frequency (EHF) ranges is challenging due to temperature-dependent phase drifts and lack of a stable reference signal in slave MMICs, affecting the coherence and reliability of radar measurements.
Innovation Solution
A method involving a master MMIC generating a local oscillator signal and a frequency-divided signal, which are transmitted to a slave MMIC, allowing for phase angle calculation by mixing the signals and using a frequency divider or multiplier to create a stable reference for phase measurement, thereby reducing phase shift and temperature-dependent drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plurality of MMICs are interconnected to emit and receive RF radar signals via multiple antennas for beam forming and direction of arrival measurement, then the radar system's functionality and measurement capability are improved, but the phase coherence between MMICs deteriorates due to temperature-dependent phase drifts and lack of stable reference signals
Solution Approach 1:
A dedicated reference signal path acts as an intermediary between the local oscillator and the slave MMIC, providing a stable phase reference that mediates the phase relationship between multiple MMICs. This separate reference path isolates the phase measurement from temperature-dependent drifts in the main signal path.
Solution Approach 2:
The system implements phase measurement and calibration by comparing the reference signal with the local oscillator signal, generating phase difference information that can be used to correct and maintain phase coherence across multiple MMICs through feedback control.
2Measurement precision
If phase measurement is performed at EHF frequencies to enable reliable radar measurement, then the measurement accuracy is improved, but the measurement process becomes more challenging due to temperature-dependent phase drifts and signal stability issues
Solution Approach 1:
The system changes the frequency parameter by dividing the EHF local oscillator signal to generate a lower frequency reference signal. This frequency transformation makes phase measurement more manageable while maintaining phase coherence information, reducing the difficulty of detection and measurement.
Solution Approach 2:
A frequency divider acts as an intermediary that transforms the high-frequency local oscillator signal into a lower-frequency reference signal, making phase measurement more feasible while preserving the phase relationship information needed for accurate radar measurements.
3Power
If the local oscillator signal is transmitted directly to the slave MMIC without frequency division, then the signal strength is maintained, but phase measurement becomes unreliable due to temperature-dependent phase drifts
Solution Approach 1:
The frequency divider serves as an intermediary that creates a derived reference signal with reduced frequency. This intermediary signal path provides a stable reference for phase measurement that is less susceptible to temperature-dependent phase drifts, while the main local oscillator signal continues to provide adequate power to the slave MMIC.
Solution Approach 2:
The signal path is segmented into two separate paths: one for power transmission (local oscillator to slave MMIC) and one for phase reference (local oscillator through frequency divider to master MMIC). This segmentation allows each path to be optimized for its specific function, maintaining signal strength while enabling reliable phase measurement.
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 enables accurate phase measurement and calibration of RF signals across MMICs, enhancing the coherence and reliability of radar systems by minimizing phase changes and temperature-induced errors.
Implementation Method 1
generating a frequency-divided signal from the local oscillator signal by means of a frequency divider arranged in the first radar chip
Implementation Method 2
generating—on the basis of the output signal of the output channel and the frequency-divided signal received by the second radar chip—a signal indicating a phase angle of the output signal relative to the received frequency-divided signal
Data Source
AI summary
A radar system and a method for a radar system are described. In accordance with one exemplary embodiment, the method includes generating a local oscillator signal in a first radar chip, generating a frequency-divided signal from the local oscillator signal by means of a frequency divider arranged in the first radar chip, transmitting the frequency-divided signal to a second radar chip, and transmitting the local oscillator signal to the second radar chip. The local oscillator signal received in the second radar chip is fed to an output channel of the second radar chip, which generates an output signal on the basis thereof. The method further includes generating—on the basis of the output signal of the output channel and the frequency-divided signal received by the second radar chip—a signal indicating a phase angle of the output signal relative to the received frequency-divided signal.