A review on RF based intruder detection using CW Doppler radar
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paper_title: Doppler Radar Architectures and Signal Processing for Heart Rate Extraction

paper_content:

In this paper heartbeat interval extraction methods using Doppler radar are reviewed. While single channel CW radar offers simple architecture and signal processing, this method is very sensitive to subject position. Quadrature radio architecture is used to overcome this limitation. The use of linear and non-linear demodulation methods was explored for heartbeat interval extraction, and it was demonstrated that heart rate variability analysis is feasible using quadrature Doppler radar.
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paper_title: A digital signal processor for Doppler radar sensing of vital signs

paper_content:

A voltage waveform signal containing respiration and heartbeat signatures is low-pass filtered (0.7 Hz) for the respiration and band-pass filtered (1.0-3.0 Hz) for the heart signal. The autocorrelation function is used to calculate the rate per minute for each of these signals. To make the processor more robust, several signal processing techniques are applied. One of these techniques, a method commonly used on audio signals for formant removal, is called center clipping. Another technique is the use of a Hanning window. To reverse the distinct shape left by the Hanning window an "undo" window is applied. The processor is programmed in LabVIEW.
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paper_title: Doppler Radar Architectures and Signal Processing for Heart Rate Extraction

paper_content:

In this paper heartbeat interval extraction methods using Doppler radar are reviewed. While single channel CW radar offers simple architecture and signal processing, this method is very sensitive to subject position. Quadrature radio architecture is used to overcome this limitation. The use of linear and non-linear demodulation methods was explored for heartbeat interval extraction, and it was demonstrated that heart rate variability analysis is feasible using quadrature Doppler radar.
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paper_title: A 2.4GHz non-contact biosensor system for continuous vital-signs monitoring

paper_content:

A non-contact vital-signs monitoring sensor system has been designed and tested. The system is assembled using two antennas instead of using one antenna and a circulator to achieve improved data accuracy with reduced DC offset. The system has been realized using a custom-designed analog baseband signal processing PCB that successfully replaces bulky baseband electronic blocks for system miniaturization. The sensor system was implemented in both single-channel and quadrature receiver configurations with the received signal being demodulated using several different algorithms. The vital-signs data extracted from a quadrature receiver with arctangent demodulation and autocorrelation method is found to be most accurate and reliable, achieving a mean error of +/- 1 beats/min vs. the reference heartbeat signal.
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paper_title: Touch-less heartbeat detection and measurement-based cardiopulmonary modeling

paper_content:

This paper presents a system for touch-less heartbeat detection and a cardiopulmonary signal modeling approach. Using a vector network analyzer, a microwave system is tested for the detection of the heartbeat signal at a distance of 1 m from a person. The proposed system shows the ability of detecting the heartbeat signals with the possibility of tuning both frequency and power. Measurements are performed at 2.4, 5.8, 10, 16, and 60 GHz, as well as at different power levels between 0 and −27 dBm. Based on measurements performed for both respiration and heart beatings, a model of the measured signals representing the cardiopulmonary activity is presented. The heartbeat rate and the heart rate variability are extracted from the modeling signal using wavelet and classic filters, for SNR between 0 and −20 dB.
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Title: A Review on RF Based Intruder Detection Using CW Doppler Radar

Section 1: INTRODUCTION
Description 1: This section introduces the motivation and background for RF-based intruder detection systems, along with their historical development and current significance.

Section 2: DOPPLER RADAR THEORY
Description 2: This section covers the fundamental principles of Doppler radar theory, explaining the Doppler Effect and its relevance to the radar-based detection system.

Section 3: METHODOLOGY
Description 3: This section details the methodology of utilizing Doppler radar for intruder detection by describing the signal processing and phase demodulation techniques involved.

Section 4: SYSTEM DESIGN
Description 4: This section explains the design architecture of the vital sign monitoring system, including different receiver designs and their respective advantages and disadvantages.

Section 5: RESULTS
Description 5: This section presents the results obtained from the microwave CW radar vital sign monitoring system, highlighting the performance under various operating frequencies and conditions.

Section 6: CONCLUSION
Description 6: This section summarizes the findings of the review, concluding the effectiveness of the RF-based detection system and suggesting potential areas for future improvement.