IR-UWB Radar Transceiver Feedthrough Cancellation
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Solution Overview
Problem
Short-range IR-UWB radar systems face a blind range issue due to high feedthrough power from the transmitter to the receiver, which overpowers the reflected signal and restricts the minimum detectable distance.
Innovation Solution
The method involves transmitting a ranging signal with a predetermined sequence of equal positive and negative pulses, and using a pulse polarity signal to digitally cancel the feedthrough portion while amplifying the reflected portion in the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional radar transmission is used, then the transmitted signal can be sent out, but the receiver cannot detect reflected signals during pulse transmission due to high feedthrough power
Solution Approach 1:
The patent converts the harmful feedthrough signal into a beneficial component by using it as a reference for digital cancellation. The feedthrough signal, which was previously obscuring the reflected signal, is now used to train the adaptive filter to learn and subtract the interference, thereby improving reflected signal detection
Solution Approach 2:
The patent changes the temporal parameters of the transmitted signal by using alternating polarities in a pulse train. This parameter modification allows the receiver to distinguish between feedthrough and reflected signals based on their different temporal characteristics, enabling effective cancellation of the feedthrough component
2Productivity
If the receiver operates during pulse transmission, then continuous monitoring is possible, but the blind range increases due to feedthrough signal dominance
Solution Approach 1:
The patent performs preliminary action by training the adaptive filter during the transmission period using the feedthrough signal as reference. This preliminary training enables the filter to be ready for cancellation before the reflected signal arrives, allowing continuous operation without increasing blind range
3Measurement precision
If digital cancellation using pulse polarity signal is applied, then feedthrough suppression is achieved, but system complexity increases
Solution Approach 1:
The patent implements feedback by using the received signal (including feedthrough) as input to the adaptive filter, which then generates a cancellation signal fed back to subtract from the received signal. This feedback mechanism automatically adapts to suppress the feedthrough component without manual intervention
Solution Approach 2:
The adaptive filter performs self-service by automatically training itself using the feedthrough signal as reference. The system self-adjusts its weights to learn the feedthrough characteristics and perform cancellation without requiring external calibration or complex manual configuration
Data Source
AI summary
A method is provided for radar ranging using an IR-UWB radar transceiver. The range is determined by measuring a time required by a transmitted pulse to be reflected by an object and returned to the transceiver. The method includes transmitting a ranging signal having a predetermined sequence of positive and negative pulses using a transmitter of the transceiver. A receiver of the transceiver receives a signal having a reflected portion and a feedthrough portion. In the method, the receiver cancels the feedthrough portion using a delayed pulse polarity signal such that when the delayed pulse polarity signal is multiplied and accumulated with the received signal, the feedthrough portion is canceled, and the reflected portion is amplified. In another embodiment, a transceiver is provided that cancels the feedthrough portion while amplifying the reflected portion. Cancelling the feedthrough portion allows short-range operation by removing a blind range of the transceiver.