Radar Leakage Suppression via Adaptive Delay Compensation
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Solution Overview
Problem
Integrated millimetre-wave frequency-modulated continuous wave (FMCW) radar systems face significant challenges due to transmitter-receiver leakage, which causes ghost targets and saturates the receiver, especially when antennas are integrated on a single chip or substrate, leading to complex and power-intensive solutions that are not effectively simple to implement.
Innovation Solution
A front-end configuration for FMCW radar systems that includes a compensation unit to correct for leakage path delays and a leakage suppression filter to remove DC components, along with a control loop for adaptive delay compensation based on maximum power detection, optimizing leakage cancellation without increasing implementation complexity or power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transmitter and receiver antennas are integrated on a single chip or substrate to reduce size, then miniaturization is achieved, but transmitter-receiver leakage increases causing ghost targets and receiver saturation
Solution Approach 1:
A leakage canceller is introduced as an intermediary component that generates a cancellation signal to counteract the leakage signal. The canceller processes the transmit signal through a leakage path model and subtracts the resulting cancellation signal from the received signal, effectively mediating between the integrated transmitter-receiver and eliminating the harmful leakage effect.
Solution Approach 2:
The leakage canceller performs preliminary anti-action by pre-generating a cancellation signal that anticipates and counteracts the leakage before it saturates the receiver. The system models the leakage path in advance and continuously subtracts the predicted leakage signal from the received signal, preventing the harmful effect rather than correcting it afterward.
2Object-affected harmful factors
If leakage cancellation is implemented using existing methods (e.g., artificial on-chip target), then leakage mitigation is achieved, but device complexity and power consumption increase due to requiring two receivers and associated circuitry
Solution Approach 1:
The leakage canceller functionality is merged with the existing single receiver circuitry rather than requiring a separate second receiver. The canceller processes signals through the same receiver chain, combining leakage cancellation with the primary detection function in a unified system, thereby reducing overall device complexity.
Solution Approach 2:
The leakage canceller is designed to perform multiple functions within a single circuit: it processes the transmit signal through the leakage model, generates the cancellation signal, and integrates it with the received signal all through the existing receiver infrastructure. This multi-functional approach eliminates the need for dedicated separate circuitry for each function.
3Object-affected harmful factors
If delay compensation is applied to correct leakage propagation time, then ghost targets are reduced, but implementation complexity increases without adaptive adjustment
Solution Approach 1:
The delay compensation is made dynamic through a control loop that continuously monitors the received signal and adjusts the delay parameter adaptively. Rather than using a fixed delay value, the system dynamically optimizes the delay compensation based on real-time signal conditions, maximizing leakage cancellation effectiveness while simplifying the overall control mechanism.
Solution Approach 2:
A control loop provides feedback from the received signal to the delay compensation mechanism. The system monitors the effectiveness of leakage cancellation and automatically adjusts the delay parameter to maintain optimal performance, creating a self-regulating system that reduces complexity by eliminating manual tuning requirements.
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 effectively compensates for leakage and phase noise in the intermediate frequency signal, preventing ghost targets and signal saturation, while being simpler and more power-efficient than existing methods, and can be implemented on a chip for integrated radar systems.
Implementation Method 1
a mixer configured for mixing the amplified signal with the reference signal to generate an output signal at intermediate frequency
Data Source
Figure 1
Figure 2a~2b
Figure 3A
AI summary
In radar systems, a leakage path may be present between transmit and receive antennas which, together with delays due to components in associated transmit and receive paths, is correlated with a reference signal resulting in a beat frequency at intermediate frequency falling within the passband of the receiver. This effect is exacerbated in millimetre-wave radars, and especially when antennas are integrated on chip. A front-end (300A) for a radar system includes a compensation unit (390) for generating a compensated reference signal (390a), which when mixed with amplified echoes (365) in mixer (370), compensates for the leakage path etc. A DC suppression filter (395) is also included which filters out DC components at intermediate frequency in output signal (375) generated as part of the compensation.