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LOU Guo,Wei,LI Xing,Guo,WU Wen,

红外与毫米波学报 , 2001,
Abstract: A 3mm wave band FMCW short range radar was studied, including the calculation of its detecting range, the design of its parameters and the analysis of its ranging precision. In addition, the measured results of the 3mm FMCW short range radar developed by the authors were presented.
FMCW Radar for Small Displacement Detection of Vital Signal Using Projection Matrix Method  [PDF]
Dan Zhang,Masahiko Kurata,Takayuki Inaba
International Journal of Antennas and Propagation , 2013, DOI: 10.1155/2013/571986
Abstract: Small displacement detection has been studied for extracting heart rate signal from the respiratory variation component of the human body with the FMCW radar method. And a new signal processing method of vital signal has been proposed for suppression of unrequired variation components called projection matrix method. We have presented experimental results of small displacement detection to confirm the validity of the method. 1. Introduction Small displacement detection technology in millimetre order at microwave band is expected to a number of applications. Some examples have been proposed such as determining biological signals of heart rate and respiration by noncontact measuring the displacement of the surface of the body and searching survivors under rubble after earthquake by detecting body movements [1–3]. We know that the CW (continuous wave) radar system and UWB pulse radar system have been used for measuring the small displacement [4]. CW radar has the advantages of low power consumption and simple radio architecture. Moreover, CW radar can also cancel out clutter noise by proper adjustment of the radio front-end architecture. The main advantages of the FMCW (frequency modulated continuous wave) radar are simple solid-state transmitters, resistance to interception, and good range resolution. FMCW method performs the velocity and range measurement, and it is considered a good solution for noncontact vital signs detection [1–3]. However, the respiration signal dominates the spectra, and its harmonics may overwhelm the heartbeat signal, making the latter invisible in the spectral analysis sign. The conventional Fourier transform method cannot reliably separate the components. Some signal processing methods are needed to solve this problem. A parametric and cyclic optimization approach, called the RELAX algorithm, has been discussed [5]. The method may take longer computation time to accurately estimate closer signals [6]. Considering these problems, in this paper, we propose a method for suppressing unnecessary periodic fluctuation component with a projection matrix. First we briefly introduce formula of FMCW method and then consider the removal method of the reflected waves from stationary objects that exist in the periphery of the body. Last we have shown the results of the experiment with radar devices that comply with specified low power radio station 24?GHz. We have verified the effectiveness of the proposed method for suppressing unnecessary fluctuation component. 2. Materials and Methods 2.1. Basic Formula As we know, the FMCW method uses
FMCW Radar Performance for Atmospheric Measurements
T. Ince
Radioengineering , 2010,
Abstract: Frequency-modulated continuous-wave radars (FMCW) have been used in the investigation of the atmosphere since the late 1960’s. FMCW radars provide tremendous sensitivity and spatial resolution compared to their pulsed counterparts and are therefore attractive for clear-air remote-sensing applications. However, these systems have some disadvantages and performance limitations that have prevented their widespread use by the atmospheric science community. In this study, system performance of atmospheric FMCW radar is analyzed and some measurement limitations for atmospheric targets are discussed. The effects of Doppler velocities and spectral widths on radar performance, radar’s near-field operation, and parallax errors for two-antenna radar systems are considered. Experimental data collected by the highresolution atmospheric FMCW radar is used to illustrate typical performance qualitatively based on morphological backscattered power information. A post-processing based on single-lag covariance differences between the Bragg and Rayleigh echo is applied to estimate clear-air component from refractive index turbulence and perform quantitative analysis of FMCW radar reflectivity from atmospheric targets.
On the radio wave propagation in the pulsar magnetosphere  [PDF]
V. S. Beskin,A. A. Philippov
Physics , 2011,
Abstract: The key properties of the wave propagation theory in the magntosphere of radio pulsars based on the Kravtsov-Orlov equation are presented. It is shown that for radio pulsars with known circular polarization and the swing of the linear polarization position angle one can determine which mode, ordinary or extraordinary one, forms mainly the mean profile of the radio emission. The comparison of the observational data with the theory predictions demonstrates their good agreement.

红外与毫米波学报 , 2001,
Abstract: 针对寄生调幅是影响FMCW毫米波雷达作用距离的重要因素,讨论了中频滤波器在FMCW毫米波雷达系统中的作用,研究了滤波器性能与雷达作用距离的关系.根据分析表明,对中频滤波器进行了CAD优化,提高了雷达的作用距离.
A FMCW Radar Distance Measure System based on LabVIEW  [cached]
Zengrong Zhao,Ran Bai
Journal of Computers , 2011, DOI: 10.4304/jcp.6.4.747-754
Abstract: This paper presents a acquisition and process system for frequency modulation continuous wave (FMCW) radar. The procedure is designed by LabVIEW7.0. The system adopts FMCW radar sensor and high-quality data acquisition card.The intermediate frequency(IF) signal of the FMCW radar can be collected in time. The intermediate frequency, distance and velocity forward vehicle can be calculated by an improved algorithm.It can give the alarm when the collide danger is predicted, and it can assist the driver to brake control, thus some collision accidents will be avoided.The design method of the system and test data are given simultaneously. The effectiveness of the designed system is verified by some real tests.
Narrowband Tracking Filters in FMCW Radar Sensors
B. Syrovatka
Radioengineering , 1995,
Abstract: The need for spectral analysis of the signal received by frequency modulated continuous wave (FMCW) radar sensors (FMRS) is inevitable in many applications of FMRS. It can be effectivelly performed using only digital signal processors, based on the fast Fourier transform (FFT). To make the signal analysis by FFT processor easier, it is necessary to separate the received signal (which generally varies in amplitude and in frequency ) from the broadband noisy background at the microwave mixer output by the narrowband tracking filter. Besides a brief desription of the performance and application of FMRS, the analysis of FMCW signal, with respect to moving target indication (MTI), and the function of a suitable tracking filter system is presented in this paper.
Radio Wave Propagation Experiment in Sugarcane Fire Environments  [PDF]
Douglas Letsholathebe, Kgakgamatso M. Mphale, Samuel Chimidza, Malcolm L. Heron
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2016, DOI: 10.4236/jemaa.2016.87013
Abstract: Large fires have an effect of suppressing Very or Ultra High Frequency (VHF/UHF) radio wave signals strength which consequently impact negatively on the efficiency of radio communications at the frequency ranges. Mobile hand-held radio operating at the frequency ranges is a major communication tool during fire suppression; therefore inefficient radio communication systems put lives of fire fighters at risk. One of the causes of signal attenuation in fire environment is plume ionization. Plume species which include graphitic carbon, alkalis and thermally excited radicals such as methyl are responsible for ionization. As atmospheric pressure ionized medium (combustion plasma), sugarcane fire has momentum transfer electron-neutral collision frequency much higher than plasma frequency, hence propagation of VHF/UHF radio waves through such a medium is predicted to suffer a significant attenuation and phase shift. Radiowave propagation measurements were carried out in a moderate intensity prescribed sugarcane fire at 151 MHz frequency over a 590 m path using a radiowave interferometer. The radio wave interferometer measured signal attenuation of 0.43 dB through the fire with maximum temperature and flame depth of 1154 K and 8.7 m, respectively.
Vikas Malik,Tejender Malik,Vikas Nandal
International Journal of Computer Science and Management Studies , 2012,
Abstract: This paper explains a approach towards the implementation of afrequency modulated continuous wave (FMCW) standard system inAdvanced Design System (ADS) software for Sub surfacepenetrating radar (SSPR). For performing experiments built-inDesign Guide has been used as reference. As, there is no modelcreated especially for SSPR investigation in ADS, therefore, thepurpose of this paper is to give an idea on how SSPR experimentresults can be simulated and analyzed without having to performthe actual experiment. ADS is used for Simulations to see how thecomponents change affects the baseband spectrum. In this paper thebasic spectrum analysis is investigated to see the relationship of thecomponents that can be tuned for further simulations.
A New Demodulation and Modulation Method Designed for FMCW Radar  [PDF]
Wei Shen,Biyang Wen
Journal of Electrical and Computer Engineering , 2010, DOI: 10.1155/2010/897429
Abstract: An efficient demodulation method designed for FMCW (Frequency-Modulated Continuous Wave) radar is presented. It is a kind of modified DFT (IDFT) algorithm; the spectrum segment of interest can be easily extracted from the original signal without calculating the whole DFT/FFT. It provides fast demodulation and extraction of desired frequency bands in our HFSWR (High-Frequency Surface Wave Radar) system. The proposed approach enhances the performances of radar system and reduces the computing complexity. The new structure could also be inversely used for signal modulation. And also arbitrary sampling rate conversion could be achieved with the combination of forward and backward structure.
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