scholarly journals A 77-GHz Six-Port Sensor for Accurate Near-Field Displacement and Doppler Measurements

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2565 ◽  
Author(s):  
Homa Arab ◽  
Steven Dufour ◽  
Emilia Moldovan ◽  
Cevdet Akyel ◽  
Serioja Tatu
Keyword(s):  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
Industrial Applications ◽  
High Signal ◽  
Millimetre Wave ◽  
Sensing Applications ◽  
Radar Sensing ◽  
Cw Radar ◽  
77 Ghz

A continuous-wave (CW) radar sensor design based on a millimetre-wave six-port interferometer is proposed. A complete sensor prototype is conceived of, fabricated and measured at 77 GHz for short-range professional and industrial applications. This sensor is designed to measure distances and Doppler frequencies with high accuracy, at a reasonable cost. Accurate phase measurements are also performed using the six-port technology, which makes it a promising candidate for CW radar sensing applications. Advances in the performance and functionality of six-port sensors are surveyed to highlight recent progress in this area. These include improvements in design, low power consumption, high signal to noise ratio, compactness, robustness and simplicity in realization. Given the fact that they are easy to fabricate, due to the lack of active circuits and being highly accurate, it is expected that six-port sensors will significantly contribute to the development of human tracking devices and industrial sensors in the near future. The entire circuit prototype, including the transmitter, the receiver antenna, the six-port interferometer and the four power detectors have been integrated on a die. The circuit is fabricated using a hybrid integrated technology on a 127-μm ceramic substrate with a relative permittivity of εr=9.8. Calibrated tuning forks are used to assess the performance of the six-port sensor experimentally for various frequencies.

scholarly journals High-speed high-resolution laser diode-based photoacoustic microscopy for in vivo microvasculature imaging

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiufeng Li ◽  
Victor T C Tsang ◽  
Lei Kang ◽  
Yan Zhang ◽  
Terence T W Wong
Keyword(s):  
High Resolution ◽  
High Speed ◽  
High Performance ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
High Signal ◽  
Photoacoustic Microscopy ◽  
Mouse Ear

AbstractLaser diodes (LDs) have been considered as cost-effective and compact excitation sources to overcome the requirement of costly and bulky pulsed laser sources that are commonly used in photoacoustic microscopy (PAM). However, the spatial resolution and/or imaging speed of previously reported LD-based PAM systems have not been optimized simultaneously. In this paper, we developed a high-speed and high-resolution LD-based PAM system using a continuous wave LD, operating at a pulsed mode, with a repetition rate of 30 kHz, as an excitation source. A hybrid scanning mechanism that synchronizes a one-dimensional galvanometer mirror and a two-dimensional motorized stage is applied to achieve a fast imaging capability without signal averaging due to the high signal-to-noise ratio. By optimizing the optical system, a high lateral resolution of 4.8 μm has been achieved. In vivo microvasculature imaging of a mouse ear has been demonstrated to show the high performance of our LD-based PAM system.

scholarly journals Distance scaling method for accurate prediction of slowly varying magnetic fields in satellite missions

2016 ◽  
Vol 5 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Panagiotis P. Zacharias ◽  
Elpida G. Chatzineofytou ◽  
Sotirios T. Spantideas ◽  
Christos N. Capsalis
Keyword(s):  
Signal To Noise Ratio ◽  
Near Field ◽  
Magnetic Behavior ◽  
Field Measurements ◽  
High Signal ◽  
Signal To Noise ◽  
Scaling Method ◽  
Magnetic Signature ◽  
The Magnetic Field

Abstract. In the present work, the determination of the magnetic behavior of localized magnetic sources from near-field measurements is examined. The distance power law of the magnetic field fall-off is used in various cases to accurately predict the magnetic signature of an equipment under test (EUT) consisting of multiple alternating current (AC) magnetic sources. Therefore, parameters concerning the location of the observation points (magnetometers) are studied towards this scope. The results clearly show that these parameters are independent of the EUT's size and layout. Additionally, the techniques developed in the present study enable the placing of the magnetometers close to the EUT, thus achieving high signal-to-noise ratio (SNR). Finally, the proposed method is verified by real measurements, using a mobile phone as an EUT.

scholarly journals A Geometric Calibration Method of Hydrophone Array Based on Maximum Likelihood Estimation with Sources in Near Field

2020 ◽  
Vol 8 (9) ◽  
pp. 678
Author(s):  
Nan Zou ◽  
Zhenqi Jia ◽  
Jin Fu ◽  
Jia Feng ◽  
Mengqi Liu
Keyword(s):  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
Likelihood Estimation ◽  
Calibration Method ◽  
Optimization Method ◽  
High Signal ◽  
Geometric Calibration ◽  
Environment Experiment

Considering the requirement of the near-field calibration under strong underwater multipath condition, a high-precision geometric calibration method based on maximum likelihood estimation is proposed. It can be used as both auxiliary-calibration and self-calibration. According to the near-field geometry error model, the objective function of nonlinear optimization problem is constructed by using the unconditional maximum likelihood estimator. The influence of multipath on geometric calibration is studied. The strong reflections are considered as the coherent sources, and the compensation strategy for auxiliary-calibration is realized. The optimization method (differential evolution, DE) is used to solve the geometry errors and sources’ position. The method in this paper is compared with the eigenvector method. The simulation results show that the method in this paper is more accurate than the eigenvector method especially under high signal-to-noise ratio (SNR) and multipath environment. Experiment results further verify the effectiveness.

A Short Distance CW-Radar Sensor at 77 GHz in LTCC for Industrial Applications

2013 ◽  
Vol 34 (12) ◽  
pp. 856-865 ◽  
Author(s):  
Christian Rusch ◽  
Tobias Klein ◽  
Stefan Beer ◽  
Thomas Zwick
Keyword(s):  
Short Distance ◽  
Industrial Applications ◽  
Radar Sensor ◽  
Cw Radar ◽  
77 Ghz

A high signal-to-noise ratio passive near-field microscope equipped with a helium-free cryostat

2017 ◽  
Vol 88 (1) ◽  
pp. 013706 ◽  
Author(s):  
Kuan-Ting Lin ◽  
Susumu Komiyama ◽  
Sunmi Kim ◽  
Ken-ichi Kawamura ◽  
Yusuke Kajihara
Keyword(s):  
Signal To Noise Ratio ◽  
Near Field ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio

Low-Cost Teleoperation of Remotely Located Actuators Based on Dual Tone Multi-Frequency Data Transfer

2011 ◽  
Vol 403-408 ◽  
pp. 4727-4734
Author(s):  
Sahil Thakkar ◽  
Animesh Garg ◽  
Adesh Midha ◽  
Prerna Gaur
Keyword(s):  
Cell Phone ◽  
Data Transfer ◽  
Signal To Noise Ratio ◽  
High Reliability ◽  
Low Cost ◽  
Control Unit ◽  
Industrial Applications ◽  
High Signal ◽  
Voice Call ◽  
Car Security

DTMF (Dual Tone Multi Frequency) is a system of signal tones used for telecommunications. DTMF uses two tones to represent each key on the touch pad. DTMF data transfer technique has advantages such as high reliability, constant speed, and high signal to noise ratio, low cost and optimal utilization of existing resources. These features make DTMF an attractive Data Transfer Technique. It finds application in home and car security systems, robot control, SMS and voice call controlled industrial applications. In this paper, we discuss the use of DTMF data transfer in a voice call to control a toy car. Cell phone 1(CP 1), which is at user end, makes a call to cell phone 2(CP 2) at the machine end and establishes a connection. A key is pressed at the user side. Two tones corresponding to one key are encoded and sent through the cell phone network. Both tones are tapped through the earphone jack of cell phone at machine end and are decoded. The output is fed to a Micro-controller. The Micro-controller is connected to the remote control unit of the toy car, which in turn controls the motion of the car. The car moves in various directions according to the key pressed user. The electronic circuit is divided into 2 parts. The transmitter side consisting of Cell phone 1 with an inbuilt encoder and the receiver side consisting of Cell Phone 2, 8870 DTMF decoder and Atmega 16 micro-controller. The programming has been carried out on AVR Bascom®.

scholarly journals Recent Progress in Fiber Optofluidic Lasing and Sensing

2021 ◽  
Vol 11 (2) ◽  
pp. 262-278
Author(s):  
Xi Yang ◽  
Chaoyang Gong ◽  
Yiling Liu ◽  
Yunjiang Rao ◽  
Mateusz Smietana ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Recent Progress ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Microfluidic Channel ◽  
High Sensitivity ◽  
Gain Medium ◽  
High Signal ◽  
Biomedical Analysis ◽  
Sensing Applications

AbstractFiber optofluidic laser (FOFL) integrates optical fiber microcavity and microfluidic channel and provides many unique advantages for sensing applications. FOFLs not only inherit the advantages of lasers such as high sensitivity, high signal-to-noise ratio, and narrow linewidth, but also hold the unique features of optical fiber, including ease of integration, high repeatability, and low cost. With the development of new fiber structures and fabrication technologies, FOFLs become an important branch of optical fiber sensors, especially for application in biochemical detection. In this paper, the recent progress on FOFL is reviewed. We focuse mainly on the optical fiber resonators, gain medium, and the emerging sensing applications. The prospects for FOFL are also discussed. We believe that the FOFL sensor provides a promising technology for biomedical analysis and environmental monitoring.

Non-Resonance Acousto-Optics Signal Analysis from Photonics Microphone Using 1 mW Laser

2016 ◽  
Vol 846 ◽  
pp. 740-747
Author(s):  
Muhammad Adib Akram Mohdami Norashid ◽  
M. Kamil Abd-Rahman
Keyword(s):  
Laser Beam ◽  
Acoustic Waves ◽  
High Speed ◽  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Free Space Optical ◽  
Signal To Noise ◽  
Optical Signals ◽  
Noise Ratio

This paper presents an acousto-optics analysis on free space optical signals modulated by two distinguishable non-resonant acoustic waves. The acoustic waves were directed at two different directions and locations along a laser beam and created non-interference modulated optical signals. The photonics microphone deploys low-powered eye-safe continuous-wave 633-nm laser; high-speed photodiode and a series of Fourier lenses. Two transducers generating 20 Hz to 20 kHz acoustic waves were directed across the laser beam. The receiving modulated signal was filtered and amplified electronically by two sets of passive bandpass filter separated by a transimpedance amplifier and connected to a computer for analysis. The signal was further digitally filtered and amplified to enhance the signal-to-noise ratio via MATLAB software. These signals were analyzed in time and frequency domains using Fast Fourier Transform (FFT) and Spectrogram. It was found that the recorded signals demonstrated higher signal intensities for lower acoustic frequencies with digital signal-to-noise ratio (SNR) ranging from 10.77 to 71.92 for frequency of 1 kHz to 20 kHz and 20 Hz to 1 kHz respectively. The frequencies of both transducers were simultaneously swept through from 20 Hz and 20 kHz respectively. These scanning frequencies approached one another and crossover with no resonant frequency was observed. This illustrates that it is able to detect multiple acoustic signals for any given frequencies along the laser beam and found its applications in stealth sound detection and long range sound sensor. Though low-powered 1-mW laser was used, a relatively high signal-to-noise ratio with clear-recorded playback was achieved.

scholarly journals Detrending Technique for Denoising in CW Radar

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6376
Author(s):  
In-Seong Lee ◽  
Jae-Hyun Park ◽  
Jong-Ryul Yang
Keyword(s):  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Circle Fitting ◽  
Polynomial Fitting ◽  
Dc Offset ◽  
Fitting Method ◽  
Measurement Results ◽  
The Time Domain ◽  
Fifth Order ◽  
Cw Radar

A detrending technique is proposed for continuous-wave (CW) radar to remove the effects of direct current (DC) offset, including DC drift, which is a very slow noise that appears near DC. DC drift is mainly caused by unwanted vibrations (generated by the radar itself, target objects, or surroundings) or characteristic changes in components in the radar owing to internal heating. It reduces the accuracy of the circle fitting method required for I/Q imbalance calibration and DC offset removal. The proposed technique effectively removes DC drift from the time-domain waveform of the baseband signals obtained for a certain time using polynomial fitting. The accuracy improvement in the circle fitting by the proposed technique using a 5.8 GHz CW radar decreases the error in the displacement measurement and increases the signal-to-noise ratio (SNR) in vital signal detection. The measurement results using a 5.8 GHz radar show that the proposed technique using a fifth-order polynomial fitting decreased the displacement error from 1.34 mm to 0.62 mm on average when the target was at a distance of 1 m. For a subject at a distance of 0.8 m, the measured SNR improved by 7.2 dB for respiration and 6.6 dB for heartbeat.

A compact guided-wave EMAT with pulsed electromagnet for ferromagnetic tube inspection

2020 ◽  
Vol 64 (1-4) ◽  
pp. 951-958
Author(s):  
Tianhao Liu ◽  
Yu Jin ◽  
Cuixiang Pei ◽  
Jie Han ◽  
Zhenmao Chen
Keyword(s):  
Power Plants ◽  
Signal To Noise Ratio ◽  
Small Diameter ◽  
Performance Testing ◽  
Guided Wave ◽  
High Signal ◽  
Receiver Coil ◽  
Signal To Noise ◽  
Corrosion Defects

Small-diameter tubes that are widely used in petroleum industries and power plants experience corrosion during long-term services. In this paper, a compact inserted guided-wave EMAT with a pulsed electromagnet is proposed for small-diameter tube inspection. The proposed transducer is noncontact, compact with high signal-to-noise ratio and unattractive to ferromagnetic tubes. The proposed EMAT is designed with coils-only configuration, which consists of a pulsed electromagnet and a meander pulser/receiver coil. Both the numerical simulation and experimental results validate its feasibility on generating and receiving L(0,2) mode guided wave. The parameters for driving the proposed EMAT are optimized by performance testing. Finally, feasibility on quantification evaluation for corrosion defects was verified by experiments.

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