scholarly journals Non-Contact Measurement of Human Respiration and Heartbeat Using W-band Doppler Radar Sensor

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5209 ◽  
Author(s):  
Heesoo Kim ◽  
Jinho Jeong
Keyword(s):  
Doppler Radar ◽  
Band Pass Filter ◽  
Radar Sensor ◽  
Pass Filter ◽  
Contact Measurement ◽  
W Band ◽  
Compact Size ◽  
Human Respiration ◽  
Low Pass ◽  
Respiration Signal

This paper presents a W-band continuous-wave (CW) Doppler radar sensor for non-contact measurement of human respiration and heartbeat. The very short wavelength of the W-band signal allows a high-precision detection of the displacement of the chest surface by the heartbeat as well as respiration. The CW signal at 94 GHz is transmitted through a high-gain horn antenna to the human chest at a distance of 1 m. The phase-modulated reflection signal is down-converted to the baseband by the quadrature mixer with an excellent amplitude and phase matches between I and Q channels, which makes the IQ mismatch correction in the digital domain unnecessary. The baseband I and Q data are digitized using data acquisition (DAQ) board. The arctangent demodulation with automatic phase unwrapping is applied to the low-pass filtered I and Q data to effectively solve the null point problem. A slow-varying DC component is rejected in the demodulated signal by the trend removal algorithm. Then, the respiration signal with a frequency of 0.27 Hz and a displacement of ~6.1 mm is retrieved by applying a low-pass filter. Finally, the respiration signal is removed by the band-pass filter and the heartbeat signal is extracted, showing a frequency of 1.35 Hz and a displacement of ~0.26 mm. The extracted respiration and heartbeat rates are very close to the manual measurement results. The demonstrated W-band CW radar sensors can be easily applied to find the angular location of the human body by using a phased array under a compact size.

Novel Low-Pass Microwave Filter Based on Rectangular Ring DGS

2013 ◽  
Vol 273 ◽  
pp. 371-374
Author(s):  
Bao Ping Li ◽  
Yan Liang Zhang
Keyword(s):  
Stop Band ◽  
Center Frequency ◽  
Pass Band ◽  
Band Pass Filter ◽  
Defected Ground Structure ◽  
Ground Structure ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Compact Size ◽  
Low Pass

Due to the frequency response periodicity of distributed transmission line, microstrip band-pass filter usually produces parasitic pass-band and outputs harmonics away from the center frequency of main pass-band. Based on the study of rectangular ring defected ground structure, a 5-order microstrip LPF(low-pass filter) was designed using the single-pole band-stop and slow-wave characteristics of the rectangular ring DGS(Defected Ground Structure) and SISS(Step-Impedance Shunt Stub) structure. Compared with traditional LPF, this LPF presents the advantages of compact size, low insertion loss, broad stop-band and high steep. It also validates the requirements of miniaturization and high performance for filters.

scholarly journals Microstrip filters Based on Open Stubs and SIR for High Frequency and Ultra-Wideband Applications

2021 ◽  
Author(s):  
Ş. Taha İmeci ◽  
◽  
Bilal Tütüncü ◽  
Faruk Bešlija ◽  
Lamija Herceg ◽  
...  
Keyword(s):  
High Frequency ◽  
Dual Band ◽  
Electrical Performance ◽  
Pass Band ◽  
Band Pass Filter ◽  
Microstrip Filter ◽  
Pass Filter ◽  
Compact Size ◽  
Low Pass ◽  
Band Pass

This paper includes two new microstrip filter configurations for high frequency and Ultra-Wide Band applications. The first proposed filter is a composition of four parallel open-circuited stubs connected by optimized fractal-structured microstrip line. The filter response is a combination of three passing regions, namely low pass from 0.1 GHz to 3 GHz, band-pass from 4.5 GHz to 9 GHz and high pass from 10.5 GHz to 13 GHz, separated by two rejection regions from 3 GHz to 4.5 GHz and 9 GHz to 10.5 GHz. Deep and sharp rejection regions reaching up to -44.6 dB with 40 % fractional bandwidth (FBW) are observed with a good electrical performance. Furthermore, with a comparative table, the advantages of this proposed BSF in terms of FBW, compactness and insertion loss are compared with recently reported related studies. Secondly a dual-band band pass filter implementing a Stepped-Impedance resonator (SIR) and a modified H-shaped structure is presented. This filter is designed to operate in a low pass region up to 3.58 GHz and a band pass region from 15.38 to 21.65 GHz, with a wide stopband region between 4.46 and 14.07 GHz. The simulated and measured results are in good agreement. Compared to its peers, the compact size and low price allow for a wide application of these filter configurations, while passing frequencies allow operation in the unlicensed frequency spectrum, which is popular for high-speed communication. Keywords: Microstrip Filter, Band Pass, Band Stop, Open Stubs, SIR.

scholarly journals W‐band dual‐band waveguide band‐pass filter using dual‐mode cavities

2018 ◽  
Vol 54 (25) ◽  
pp. 1444-1446
Author(s):  
Jianfei Chen ◽  
Sheng Zhang ◽  
Chao Zhang ◽  
Yuehua Li
Keyword(s):  
Dual Band ◽  
Band Pass Filter ◽  
Dual Mode ◽  
Pass Filter ◽  
W Band ◽  
Band Pass

Miniaturized Bandpass Filter with Wide Stopband using Spiral Configuration of Stepped Impedance Resonator

Frequenz ◽  
2018 ◽  
Vol 72 (9-10) ◽  
pp. 455-458 ◽  
Author(s):  
Vivek Singh ◽  
Vinay Kumar Killamsetty ◽  
Biswajeet Mukherjee
Keyword(s):  
Bandpass Filter ◽  
Short Circuit ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Transmission Zeros ◽  
Quarter Wavelength ◽  
Rejection Level ◽  
Compact Size ◽  
Band Pass ◽  
Stepped Impedance Resonator

Abstract In this letter, a miniaturized Band Pass Filter (BPF) with wide stopband centered at 0.350 GHz for TETRA band applications is proposed using a Spiral Short Circuit quarter wavelength Stepped Impedance Resonator (SSC-SIR) and a stub loaded on feed line for enhancement of rejection level in the stopband. Spiral configuration of the resonator is used for the miniaturization of BPF. The proposed BPF provides a 3dB fractional bandwidth of 13.7 % with two transmission zeros in the lower and upper stopband to provide good selectivity and four transmission zeros which provide wide stopband upto 6.86f0. Proposed BPF has a very compact size of 0.064λg×0.062λg.

scholarly journals Excitation Schemes of Plasmonic Angular Ring Resonator-Based Band-Pass Filters Using a MIM Waveguide

Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 41 ◽  
Author(s):  
Vishwanath Mittapalli ◽  
Habibulla Khan
Keyword(s):  
Ring Resonator ◽  
Simulation Software ◽  
Ring Resonators ◽  
Band Pass Filter ◽  
Pass Filter ◽  
Analysis And Design ◽  
Compact Size ◽  
Metal Insulator Metal ◽  
Band Pass ◽  
Mim Waveguide

This article describes the analysis and design of the excitation schemes of the plasmonic angular ring resonator-based band-pass filters using a metal-insulator-metal (MIM) waveguide. The excitation schemes of the plasmonic angular ring resonator-based band-pass filters have been analyzed in terms of their physical length by using commercially available electromagnetic full-wave simulation software (CST microwave studio). The excitation schemes of the plasmonic angular ring resonator-based band-pass filter using a MIM waveguide have been realized at the optical O (1260–1360 nm) and U (1625–1675 nm) bands, respectively, as it has dual-band characteristics. The excitation schemes of the plasmonic angular ring resonators have been designed and simulated to determine the variation in transmission and reflection coefficients. The magnetic field distribution of the proposed filters was observed. The ring resonators require low power and had a compact size, which was further used for the development of photonic integrated circuits (PICs). The applications of these resonators are further extended and they are used in the development of antennas, branch line couplers, directional couplers and diplexers.

scholarly journals Software-Defined Doppler Radar Sensor for Human Breathing Detection

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3085 ◽  
Author(s):  
Sandra Costanzo
Keyword(s):  
Software Defined Radio ◽  
Doppler Radar ◽  
Low Cost ◽  
Vital Signs ◽  
Phase Correlation ◽  
Wireless Sensing ◽  
Radar Sensor ◽  
Human Respiration ◽  
Critical Issues ◽  
Radio Transceiver

Non-contact wireless sensing approaches have emerged in recent years, in order to enable novel enhanced developments in the framework of healthcare and biomedical scenarios. One of these technologically advanced solutions is given by software-defined radar platforms, a low-cost radar implementation, where all operations are implemented and easily changed via software. In the present paper, a software-defined radar implementation with Doppler elaboration features is presented, to be applied for the non-contact monitoring of human respiration signals. A quadrature receiver I/Q (In-phase/Quadrature) architecture is adopted in order to overcome the critical issues related to the occurrences of null detection points, while the phase-locked loop components included in the software defined radio transceiver are successfully exploited to guarantee the phase correlation between I/Q signal components. The proposed approach leads to a compact, low-cost, and flexible radar solution, whose application abilities may be simply changed via software, with no need for hardware modifications. Experimental results on a human target are discussed so as to demonstrate the feasibility of the proposed approach for vital signs detection.

scholarly journals A CMOS Low Pass Filter for SoC Lock-in-Based Measurement Devices

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5173 ◽  
Author(s):  
Jorge Pérez-Bailón ◽  
Belén Calvo ◽  
Nicolás Medrano
Keyword(s):  
Dynamic Range ◽  
Current Trend ◽  
Cutoff Frequency ◽  
Oxide Semiconductor ◽  
Constant Current ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Compact Size ◽  
Low Pass ◽  
Lock In

This paper presents a fully integrated Gm–C low pass filter (LPF) based on a current steering Gm reduction-tuning technique, specifically designed to operate as the output stage of a SoC lock-in amplifier. To validate this proposal, a first-order and a second-order single-ended topology were integrated into a 1.8 V to 0.18 µm CMOS (Complementary Metal-Oxide-Semiconductor) process, showing experimentally a tuneable cutoff frequency that spanned five orders of magnitude, from tens of mHz to kHz, with a constant current consumption (below 3 µA/pole), compact size (<0.0140 mm2/pole), and a dynamic range better than 70 dB. Compared to state-of-the-art solutions, the proposed approach exhibited very competitive performances while simultaneously fully satisfying the demanding requirements of on-chip portable measurement systems in terms of highly efficient area and power. This is of special relevance, taking into account the current trend towards multichannel instruments to process sensor arrays, as the total area and power consumption will be proportional to the number of channels.

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