• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.234-239
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• 2012

This paper presents a compact K-band Doppler radar sensor for human vital signal detection that uses a radar configuration with only single coupler. The proposed radar front-end configuration can reduce the chip size and the additional RF power loss. The radar front-end IC is composed of a Lange coupler, VCO, and single balanced mixer. The oscillation frequency of the VCO is from 27.3 to 27.8 GHz. The phase noise of the VCO is -91.2 dBc/Hz at a 1 MHz offset frequency, and the output power is -4.8 dBm. The conversion gain of the mixer is about 11 dB. The chip size is $0.89{\times}1.47mm^2$. The compact Ka-band Doppler radar system was developed in order to demonstrate remote human vital signal detection. The radar system consists of a Ka-band Doppler radar module with a $2{\times}2$ patch array antenna, baseband signal conditioning block, DAQ system, and signal processing program. The front-end module size is $2.5{\times}2.5cm^2$. The proposed radar sensor can properly capture a human heartbeat and respiration rate at the distance of 50 cm.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.2
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• pp.75-81
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• 2009

In this paper, Microwave doppler radar sensor operated in 10.525GHz is designed by dielectric resonant oscillator. According to doppler effects, a characteristic of Microwave sensor with FMCW was analyzed. The qualities of objects velocity and distance between object and microwave sensor by sensor output frequency difference was measured. As a result of Microwave doppler radar sensor, the prototype sensor is available for indoor burglar alarms and other application through FMCW signal.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.75-82
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• 2001

In this paper, a transmitter and a receiver using a Gunn diode and SBD was designed and fabricated in X-band. This system detects Doppler shift signal reflected by moving target through the homodyne detection, which is Doppler radar sensor for the measurement of the velocity of moving target. By the experimental results, the oscillating condition of the transmitter was satisfied at about the half wavelength between the supporting post of the Gunn diode in the waveguide and the waveguide short. And using the fabricated Doppler radar sensor, the velocity measurement deviation of moving target was 1.24%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.623-628
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• 2015

The paper produced an application that used Doppler radar sensor to prevent bicycle related accidents. Doppler radar sensor detects any approaching object and gives warning to the user through the danger detection algorithm of the application. The danger detection algorithm determines danger by comparing relative speed using the sensed approaching object and Doppler frequency. It also sends SMS to the preset contact to let him/her be informed of the critical situation in which the user lies when an accident happens. The experiment result showed that the algorithm judged danger by detecting the approach status and speed as well as sent out SMS to the set contact under the assumption that there was an accident.

• Journal of Biosystems Engineering
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• v.25 no.3
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• pp.233-240
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• 2000

A commercially available Doppler radar was modified and evaluated for on-board monitoring of ground speed. The radar output was corrected for pitch angle of aircraft based on the output of an electrolytic tilt sensor. The effects of aircraft speed, height and mounting angle on error in the ground speed were evaluated. The speed error decreased with an increase of the mounting angle since the radar contact angle with respect to the ground approached to the mounting angle. The error increased with an increase of the nominal aircraft speed. The altitude insignificantly affected the speed error. The Doppler radar provided acceptable percent errors within 5% in most measurements. The error can be reduced within ${\pm}$1.5% by increasing the mounting angle ($43^{\circ}$). The error of -3.8% at the mounting angle of $29^{\circ}$could be reduced by adjusting the mounting angle with respect to the radar contact angle.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.931-936
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• 2018

We designed an x-band radar for motion detector using a frequency tunable hairpin ring resonator. The proposed doppler radar sensor can vary the oscillation frequency by applying a hairpin resonator using a varactor diode to the oscillator, and this can also reduce the size by transmitting and receiving a signal from Tx/Rx dual antenna. The fabricated doppler radar sensor was fabricated in $30{\times}24mm$, and it was confirmed that the pulse width difference occurred according to the distance from the object. The measurement results showed oscillation at 10.525GHz. We confirmed that it is enough to use as radar for motion detection from the measured results.

• Journal of Biomedical Engineering Research
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• v.38 no.5
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• pp.264-270
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• 2017

A Doppler radar sensor was applied to detect respirations and heartbeats of persons who were lying on a bed. This study is preliminary study aiming at non-contact and non-intrusive respiration and heart rate monitoring during sleep in daily life. For the experiments, 10GHz Doppler radar with patch-type antenna was used and installed on the upper right and the distance between the body and the antenna was 1 m. The results show that each signal of respiration and heartbeat is observed in each frequency band however the frequency band and the waveform vary according to the subjects and the posture. The results show that the heartbeats can be detected with the peak detection in some frequency band. This study shows the feasibility of applying the Doppler radar to detection of heartbeat and respiration during sleep and further studies about heartbeat detection algorithm are required.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.552-554
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• 2021

We propose a fall recognition system using a deep learning algorithm using motion data acquired by a Doppler radar sensor. Among the deep learning algorithms, an RNN that has an advantage in time series data is used to recognize falls. The fall data of the Doppler radar sensor has a temporal characteristic as time series data, and the structure of the RNN is sequenced because the result only determines whether a fall or not It is designed in a structure that outputs a fixed size to the input.

• Journal of Sensor Science and Technology
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• v.12 no.4
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• pp.185-190
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• 2003

Recently, sensors which use the infrared light, supersonic waves, and electromagnetic waves have been used for many applications to detect information of the object. For these sensors, the accompanying system which utilizes the sensor should be systematically developed. In this paper, a general microwave radar sensor system is briefly described, and then basic applications of a CW doppler radar sensor system are introduced. For the CW doppler radar sensor applications, a highly-stable, low-cost Dielectric Resonator Oscillator (DRO) has also been designed and implemented, which can be used for commercial microwave sensor systems. The implemented DRO has output power of +5.33 dBm at 12.67 GHz and phase noise of -108.5 dBc/Hz at the 100 kHz offset frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.580-588
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• 2009

A Missile Warning Radar is an essential sensor for active protection system to detect antitank missile in all weather environments. This paper presents the design, development, and test results of L-band pulsed Doppler radar system for main battle tank. This radar system consists of 3 LRUs, which include antenna unit, transmitter and receiver unit and radar signal & data processing unit. The developed core technologies include the patch antenna, SSPA transmitter, coherent I/Q detector, DSP based Doppler FFT filter, adaptive CFAR, SIW tracking capability, and threat decision. The design performance of the developed radar system is verified through various ground fixed and moving vehicle test.