scholarly journals Ultra-wideband chaotic radio pulse reception in the case of inter-pulse interference

2019 ◽  
Vol 30 ◽  
pp. 03009
Author(s):  
Lev Kuzmin ◽  
Alexander Grinevich

The problem of receiving ultra-wideband (UWB) chaotic radio pulses of microwave band that passed through a multipath channel is considered. Based on measurements of UWB chaotic radio pulse propagation through a real wireless channel, a method for reception is proposed that is not affected by interpulse interference.

Author(s):  
Л.В. Кузьмин ◽  
А.В. Гриневич

The blind detection of ultra-wideband (UWB) chaotic radio pulses of microwave band in multipath channel is considered. Based on the measurement results of propagation of UWB chaotic radio pulses in a real wireless channel, a method for their detection is proposed that is not affected by interpulse interference.


Antennas ◽  
2021 ◽  
Author(s):  
M. M. Ivoylova ◽  
A. V. Kashin ◽  
V. A. Kozlov

The current trend in the development of radio engineering systems (RES) is to use wide spectrum signals, the application of which provides an increase in the resolution and secrecy of the radar operation, an increase in the speed and volume of transmitted information for communication and telemetry systems. The class of such signals includes ultrashort pulses (USP signals), radio pulses with linear frequency modulation (chirp signals). Also of interest are ultra-wideband (UWB) noise signals (UWBN signals), which have high electromagnetic compatibility, stealth and noise immunity. When designing promising ground-based and space-based RES using wide spectrum signals, an important task is to determine the distortions of their envelope shape and distortions of spectrum, as well as the change in the polarization of the emitted wave when passing through the Earth's ionosphere, since taking these distortions into account will provide conditions for optimal reception. This article presents the numerical assessment results of the expected distortions of the wide spectrum signals main types of the decimeter wavelength range, for middle latitudes at heights from 100 km to 1000 km. The conversion of the emitted pulse into a frequency modulated radio pulse is typical for the USP signal. For a chirp radio pulse with a monotonically increasing frequency, an initial decrease in duration with an increase in amplitude and subsequent stretching in time with further spread is typical (the amplitude change is estimated due to a change in the signal shape without taking into account spread). For a chirp radio pulse with a monotonically falling frequency and a UWBN signal, dispersion distortions manifest themselves as an increase in their duration with a decrease in amplitude. For all signal types under consideration that have passed through the ionosphere, a leading edge lag is observed, the dependences of frequency on time at an altitude of 1000 km are repeated and are close to hyperbolic character, the energy spectra envelope shape of the considered signals is almost not distorted. The polarization plane rotation for signals with a spectrum concentrated in the frequency range above 0.7 GHz does not exceed 45


Author(s):  
Kedar Nath Sahu ◽  
Challa Dhanunjaya Naidu ◽  
Ravindharan Ethiraj ◽  
Jaya Sankar Kottareddygari

The measurement, monitoring of heartbeat and its rate are necessary to know the health of the heart of human beings. In addition, they are needed for extended applications like criminal investigation, law enforcement, defense and military usage, search, rescue operation, etc. The ultra-wideband (UWB) radars found growing interest in recent years as they are able to overcome the limitations of continuous-wave (CW) Doppler radars in detecting human heartbeat. Modeling and analysis of the UWB pulse propagation behavior through a human body is important before developing a practical UWB radar. Several researchers have estimated the reflected signals to study if their variations correlate with the heartbeat rate. However, the reflected signal strength carrying Doppler information received at the radar after a two-way propagation of the RF signal was found to be too weak for detection. This paper presents (i) a model for UWB wave propagation through a human thorax and (ii) estimation via simulation, of transmission coefficient at various frequencies in the UWB range 1–10[Formula: see text]GHz using CST Microwave Studio. The study clearly indicates that the variation of power transmission coefficient of UWB signal has a strong correlation to the instantaneous dimension of the heart in a cardiac cycle, a feature that can be exploited in detecting cardiac activity of human being using radar-based principles.


Author(s):  
Ayse Adalan ◽  
Michael Fischer ◽  
Thomas Gigl ◽  
Klaus Witrisal ◽  
Arpad L. Scholtz ◽  
...  

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
K.V. Muzalevskiy ◽  

This article presents the results of measuring the moisture content of 6 cm topsoil using a radio impulse with a central frequency of 693 MHz, emitted and received by a log-periodic antenna the radiation pattern of which is oriented on the nadir. Measurements of the reflection coefficient at the center frequency of the radio impulse were carried out from May 25 to July 8, 2020 in an agricultural field sown with wheat in the area of Minino village (56.08676 North Sh., 92.67944 East D.), Krasnoyarsk region. In the course of the experiments, the height of the wheat was from ~ 10cm to ~ 60cm. Radio impulses were formed and recorded using an Agilent N9918A FieldFox vector network analyzer connected to the antenna output. The method for estimating the reflection coefficient consisted in measuring the maximum of the envelope of the radio impulse reflected from the soil cover relative to the maximum of the envelope of the radio impulse reflected from the metal sheet placed on the soil cover. It has been experimentally established that neglecting the influence of wheat vegetation up to 60 cm in height leads to an underestimation of the retrieved soil moisture by 0.05 cm3/cm3. It is shown that a simple model describing the attenuation of a radio impulse in the vegetation cover according to an exponential law, with a determination coefficient of 0.976 and a standard deviation of 0.03 cm3/cm3, makes it possible to retrieved soil moisture in the surface layer of 0-6 cm thick at various stages of wheat growing no more than 60 cm high. The author sees the indisputable advantage of using ultra-wideband pulsed signals, the spectrum of which is concentrated in the megahertz frequency range, for the further development of technology for remote measurement of moisture in the arable layer of agricultural soils.


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