Short-Range Radar Receiver Attenuation Circuit for Coupling Control
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Solution Overview
Problem
Short-range radars face challenges in detecting targets due to coupling phenomena between the transmitter and receiver, which can overwhelm the low-noise amplifier and hinder accurate echo detection.
Innovation Solution
Incorporating an attenuation circuit with insulated-gate field-effect transistors (IGFETs) between the receiving antenna and the low-noise differential amplifier, controlled to switch between operating modes to manage signal attenuation, effectively blocking unwanted coupling signals while allowing echo detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the receiver is placed close to the transmitting antenna to enable short-range detection, then the detection range is improved, but coupling phenomena between transmitter and receiver increase causing detection errors
Solution Approach 1:
An attenuation circuit is introduced as an intermediary component between the receiving antenna and the low-noise amplifier. This circuit selectively attenuates strong coupling signals from the transmitter while allowing weaker echo signals to pass through, thereby enabling short-range detection without suffering from transmitter-receiver coupling interference
Solution Approach 2:
The attenuation circuit dynamically adjusts its attenuation level based on the operating mode. In the first operating mode, it provides strong attenuation to block coupling signals during transmission phases, while in the second operating mode, it reduces attenuation to allow echo signals to be amplified by the low-noise amplifier, thus adapting to different signal conditions
2Measurement precision
If the low-noise amplifier amplifies all incoming signals to improve sensitivity, then echo detection sensitivity is improved, but coupling signals overwhelm the amplifier causing detection failure
Solution Approach 1:
The attenuation circuit performs preliminary action by attenuating strong coupling signals before they reach the low-noise amplifier. This prevents the amplifier from being overwhelmed by excessive signal levels, allowing it to maintain its high sensitivity for detecting weak echo signals without distortion or saturation
Solution Approach 2:
The attenuation circuit applies different attenuation levels to different signal components based on their characteristics. It provides strong attenuation specifically for the direct coupling signals from the transmitter while applying minimal attenuation to the weaker echo signals that arrive at different times, thus preserving the sensitivity needed for echo detection
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
The solution provides rapid and significant attenuation of coupling signals, protecting the low-noise amplifier and ensuring accurate detection of targets, even at close ranges, with minimal impact on desired echo signals.
Implementation Method 1
an attenuation circuit interposed between the receiving antenna and the low-noise differential amplifier, the attenuation circuit comprising at least first, second, third, and fourth transistors
Data Source
AI summary
The present description concerns a radar apparatus comprising an electromagnetic wave receiver comprising an antenna for receiving electromagnetic waves coupled to an integrated circuit comprising a low-noise differential amplifier and an attenuation circuit interposed between the receiving antenna and the low-noise differential amplifier, the attenuation circuit comprising at least first, second, third, and fourth transistors.