Multi-Chip Radar Phase Feedback for Coherent Beamforming
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Solution Overview
Problem
Radar systems with multiple transmission and reception channels face challenges in maintaining coherent RF signals with defined phases across multiple antennas, which is crucial for accurate angular position measurement and beamforming techniques, but existing technologies struggle to efficiently measure and adjust phase shifts due to variations in signal paths and temperature influences.
Innovation Solution
A radar system architecture that includes a master radar chip generating an RF oscillator signal and a feedback circuit in a slave chip to reflect or decouple part of the signal, allowing for phase shift measurement through a coupler and measurement circuit, enabling precise phase adjustment and calibration across multiple channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple radar chips are used to provide multiple TX and RX channels for MIMO and beamforming, then the angular measurement capability and spatial resolution are improved, but the phase coherence across channels deteriorates due to signal path variations and temperature influences
Solution Approach 1:
The patent implements a feedback mechanism where the phase of the local oscillator signal is measured at each radar chip and fed back to a central controller. The controller then adjusts the phase of the LO signal at each chip to compensate for path variations, maintaining phase coherence across all channels despite using multiple chips for MIMO and beamforming operations
Solution Approach 2:
The system dynamically adjusts the phase parameter of the local oscillator signal at each radar chip based on measured phase deviations. By changing the phase parameter in response to temperature and path variations, the system maintains coherent phase relationships across multiple channels while enabling advanced angular measurement capabilities
2Device complexity
If the local oscillator signal is distributed across multiple radar chips, then the system complexity is reduced compared to separate oscillators, but the phase shift measurement and adjustment capability deteriorates without additional measurement circuits
Solution Approach 1:
The measurement circuit at each radar chip serves multiple functions: it measures the phase of the distributed LO signal, provides feedback for phase correction, and enables calibration of the entire multi-chip system. This universal measurement capability allows the system to maintain phase coherence while using a simplified distributed oscillator architecture
Solution Approach 2:
The patent introduces a measurement circuit as an intermediary between the distributed local oscillator and the signal processing chains. This intermediary measures phase deviations and enables correction without requiring complex modifications to the core oscillator distribution architecture, thus maintaining simplicity while enabling precise phase control
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 solution allows for accurate phase measurement and adjustment, enhancing the angular measurement capabilities of radar systems by compensating for phase changes caused by signal path variations and temperature effects, thereby improving the precision of object localization.
Implementation Method 1
A feedback circuit arranged in the second radar chip is connected to the second RF contact in a switchable manner and is configured to reflect at least part of the RF oscillator signal arriving over the RF line as RF feedback signal
Implementation Method 2
A measurement circuit arranged in the first radar chip and coupled to the first RF contact via a coupler receives the RF feedback signal
Data Source
AI summary
A radar system includes a first radar chip with a first RF contact, a second radar chip with a second RF contact, an RF signal path connecting the first RF contact to the second RF contact, and a local oscillator arranged in the first radar chip and configured to generate an RF oscillator signal, and which is coupled to the first RF contact to transmit the RF oscillator signal to the second radar chip. A feedback circuit arranged in the second radar chip is switchably connected to the second RF contact and is configured to reflect at least part of the RF oscillator signal arriving over the RFRF signal path as an RF feedback signal. A measurement circuit, arranged in the first radar chip, coupled to the first RF contact via a coupler receives the RF feedback signal and is configured to determine a signal that represents a phase shift.