Quadrature Frequency-Group Radar and its center estimation algorithms for small Vibrational Displacement

Kim, Dong Kyoo; Kim, Youjin

doi:10.1038/s41598-019-43205-7

Cited by 21 publications

(5 citation statements)

References 32 publications

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“…As a kind of CW radar, Doppler radar is a promising technology for low-power displacement sensing applications， as shown in Fig. 1 [11]. Doppler radar system uses a directconversion, which reduces power consumption compared to other radar systems like frequency-modulated continuous wave (FMCW) radar.…”

Section: A Doppler Radarmentioning

confidence: 99%

A Review on Recent Advancements of Biomedical Radar for Clinical Applications

Dong,

Wen,

et al. 2024

IEEE Open J. Eng. Med. Biol.

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The field of biomedical radar has witnessed significant advancements in recent years, paving the way for innovative and transformative applications in clinical settings. Most medical instruments invented to measure human activities rely on contact electrodes, causing discomfort. Thanks to its noninvasive nature, biomedical radar is particularly valuable for clinical applications. A significant portion of the review discusses improvements in radar hardware, with a focus on miniaturization, increased resolution, and enhanced sensitivity. Then, this paper also delves into the signal processing and machine learning techniques tailored for radar data. This review will explore the recent breakthroughs and applications of biomedical radar technology, shedding light on its transformative potential in shaping the future of clinical diagnostics, patient and elderly care, and healthcare innovation.

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Section: A Doppler Radarmentioning

confidence: 99%

A Review on Recent Advancements of Biomedical Radar for Clinical Applications

Dong,

Wen,

et al. 2024

IEEE Open J. Eng. Med. Biol.

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“…In Doppler radar transceivers, quadrature receivers are employed to prevent the phase demodulation null points problem ( Yavari et al, 2015 ). Channel imbalance generates large inaccuracies in displacement measurement ( Yavari et al, 2015 ) and changes the forms of physiological signals, leading to errors in the effective radar cross-section and breathing rate estimate in Doppler radar physiological monitoring ( Yavari et al, 2015 ; Kim and Kim, 2019 ). Single-channel receiver architectures can solve this problem, however, they necessitate complicated coherent signal production and higher sampling rates ( Yavari et al, 2015 ; Kim and Kim, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Through the wall human heart beat detection using single channel CW radar

Pramanik,

Islam

2024

Front. Physiol.

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Single-channel continuous wave (CW) radar is widely used and has gained popularity due to its simple architecture despite its inability to measure the range and angular location of the target. Its popularity arises in the industry due to the simplicity of the required components, the low demands on the sampling rate, and their low costs. Through-the-wall life signs detection using microwave Doppler Radar is an active area of research and investigation. Most of the work in the literature focused on utilizing multi-channel frequency modulated continuous wave (FMCW), CW, and ultra-wideband (UWB) radar for their capability of range and direction of arrival (DOA) estimation. In this paper, through-the-wall single-subject and two-subject concurrent heart rate detection using single-channel 24-GHz CW radar leveraged with maximal overlap discrete wavelet transform (MODWT) is proposed. Experimental results demonstrated that the repetitive measurement of seven different subjects at a distance of 20 cm up to 100 cm through two different barriers (wood and brick wall) showed an average accuracy of heart rate extraction of 95.27% for varied distances (20–100 cm) in comparison with the Biopac ECG acquisition signal. Additionally, the MODWT method can also isolate the independent heartbeat waveforms from the two subjects’ concurrent measurements through the wall. This involved four trials with eight different subjects, achieving an accuracy of 97.04% for a fixed distance of 40 cm from the Radar without estimating the angular location of the subjects. Notably, it also superseded the performance of the direct FFT method for the single subject after 40 cm distance measurements. The proposed simpler architecture of single-channel CW radar leveraged with MODWT has several potential applications, including post-disaster search and rescue scenarios for finding the trapped, injured people under the debris, emergency evacuation, security, surveillance, and patient vital signs monitoring.

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“…One primary research focus of quadrature CW radar is to reduce the in-phase and quadrature-phase (IQ) imbalance and eliminate the direct current (DC) offset for accurate phase demodulation. Studies on heterodyne demodulation architectures [ 4 ], six-port interferometers [ 5 ], frequency group radars [ 6 ], and nonlinear channel combining algorithms [ 7 ] have shown promising results for solving this problem. After center and imbalance correction, the Doppler phase shift of the CW signal can be accurately demodulated to determine the small, time-varying displacement of the chest wall due to breathing.…”

Section: Introductionmentioning

confidence: 99%

Frequency Comb-Based Ground-Penetrating Bioradar: System Implementation and Signal Processing

Gidion

Aftab

et al. 2023

Sensors

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Radars can be used as sensors to detect the breathing of victims trapped under layers of building materials in catastrophes like earthquakes or gas explosions. In this contribution, we present the implementation of a novel frequency comb continuous wave (FCCW) bioradar module using a commercial software-defined radio (SDR). The FCCW radar transmits multiple equally spaced frequency components simultaneously. The data acquisition of the received combs is frequency domain-based. Hence, it does not require synchronization between the transmit and receive channels, as time domain-based broadband radars, such as ultra wideband (UWB) pulse radar and frequency-modulated CW (FMCW) radar, do. Since a frequency comb has an instantaneous wide bandwidth, the effective scan rate is much higher than that of a step frequency CW (SFCW) radar. This FCCW radar is particularly suitable for small motion detection. Using inverse fast Fourier transform (IFFT), we can decompose the received frequency comb into different ranges and remove ghost signals and interference of further range intervals. The frequency comb we use in this report has a bandwidth of only 60 MHz, resulting in a range resolution of up to 2.5 m, much larger than respiration-induced chest wall motions. However, we demonstrate that in the centimeter range, motions can be detected and evaluated by processing the received comb signals. We want to integrate the bioradar into an unmanned aircraft system for fast and safe search and rescue operations. As a trade-off between ground penetrability and the size and weight of the antenna and the radar module, we use 1.3 GHz as the center frequency. Field measurements show that the proposed FCCW bioradar can detect an alive person through different nonmetallic building materials.

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Quadrature Frequency-Group Radar and its center estimation algorithms for small Vibrational Displacement

Cited by 21 publications

References 32 publications

A Review on Recent Advancements of Biomedical Radar for Clinical Applications

A Review on Recent Advancements of Biomedical Radar for Clinical Applications

Through the wall human heart beat detection using single channel CW radar

Frequency Comb-Based Ground-Penetrating Bioradar: System Implementation and Signal Processing

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