Anti-Interference Microwave Detection Module Frequency Selection
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Solution Overview
Problem
Conventional microwave detectors face significant interference from electromagnetic radiation, particularly from lower frequency bands, which affects the accuracy of detecting human body movements and fails to meet stringent certification standards due to incomplete feedback and filtering limitations.
Innovation Solution
An anti-interference microwave detection module utilizing frequency-selection and low-pass filtering processes to reduce interference from electromagnetic radiations, specifically using a frequency-selection network and Butterworth low pass filters to enhance detection accuracy and comply with certification standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional microwave detectors operate in license-free frequency bands (e.g., 5.8 GHz) to enable widespread deployment, then device accessibility and application scope are improved, but electromagnetic radiation interference from lower frequency bands increases detection inaccuracy
Solution Approach 1:
The patent introduces an intermediary frequency-selection network between the receiving antenna and the mixing circuit. This network selectively passes the excitation frequency signal while blocking lower frequency interference signals, thereby mediating between the need to operate in license-free bands and the need to reject electromagnetic interference from lower bands
Solution Approach 2:
The patent changes the frequency parameter of the detection system by using frequency up-conversion. The original baseband Doppler signal is modulated onto a higher frequency carrier (excitation frequency), which then passes through the frequency-selection network that blocks lower frequency interference while allowing the modulated signal through
2Object-affected harmful factors
If the Doppler intermediate-frequency signal is directly filtered to remove lower frequency components, then interference rejection is improved, but movement characteristic information is lost
Solution Approach 1:
The patent performs preliminary frequency up-conversion before filtering. By first modulating the Doppler signal onto a higher frequency carrier and then applying frequency-selection filtering, the system achieves interference rejection while preserving the movement characteristic information embedded in the frequency-shifted signal
3Measurement precision
If frequency-selection networks are added to the microwave detection module to reduce electromagnetic interference, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The frequency-selection network serves multiple functions simultaneously: it acts as a band-pass filter to block lower frequency interference, serves as an impedance matching network for the receiving antenna, and provides signal routing functionality. This multi-functionality reduces the need for separate components and mitigates the increase in device complexity
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 module effectively reduces interference from electromagnetic radiations, providing accurate detection of human body movements and meeting certification standards by filtering out unwanted signals and enhancing the feedback of movement characteristics.
Implementation Method 1
frequency-selection processing the echo signal; frequency-selection network selectively allows the electrical signal of a specific frequency interval to pass through
Implementation Method 2
generating a Doppler intermediate-frequency signal corresponding to a frequency difference of the excitation signal and the echo signal based on the Doppler effect
Data Source
AI summary
An anti-interference microwave detection module processes frequency-selection for reducing the interferences from the electromagnetic radiation of the frequency bands different from the frequency band of the anti-interference microwave detection module in the environment to the echo signal of the anti-interference microwave detection module. A Doppler intermediate-frequency signal is trend processed to obtain a fluctuation signal. The characteristic parameter of the fluctuation of the fluctuation signal is corresponding to the characteristics of the movement of the object in the detection space, so that the anti-interference microwave detection module is able to completely reflect the characteristics of the movement of the object in the detection space and reduce the interferences of the electromagnetic radiation in the environment, including the interferences of the electromagnetic radiation of the same frequency band of the anti-interference microwave detection module, to the fluctuation signal.