The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this work the single-level model for determination of the constant of radiating change of lifetime of minority carriers in the base of n-p-n transistors, also DLTS spectra in the base area of n-p-n transistors are modeled and results of calculations are obtained.
A new mathematical model of the clutter in the form of conditional linear random process has been justified. The impulsive components of the radar noise as well as continuous fluctuations can be represented by the model. The distribution of conditional linear random process is represented by its characteristic function and it is the mixture of infinitely divisible distributions.
In many cases one can be faced with situation of unknown and unstable statistical models of signals and interferences. In this paper the nonparametric approach to synthesis of signal detection algorithms is considered in conditions of the nonparametric aprioristic uncertainty of signal and interference situations
The license plate location is an essential process in the license plate recognition system, and has been studied widely. In view of vehicles image on different background and light densities, this paper presents a license plate location algorithm based on combinatorial feature. Firstly, we propose to preprocess the image of license plate with traditional but rapid method. Secondly, we define some...
The Cassini RADAR is a Ku band multimode instrument capable of providing topography information of Titan's surface when operating in altimetry mode. During the last six years (January 2005 to 2011) Cassini has performed 71 Titan's fly-bys and several observations have been collected in Altimetry mode. These profiles have shown Titan's surface complexity. Along track profile resolution can be improved...
This paper presents a novel negative differential resistance (NDR) voltage-controlled oscillator (VCO) for microwave applications. The VCO circuit comprises a high electron mobility field-effect transistor (HEMT) and a p-channel metal-oxide-semiconductor transistor (PMOST) current mirror (CM). The mathematical model of the proposed VCO is developed. The designed VCO uses a pseudomorphic HEMT NE3210S01...
The superheterodyne amplification of electromagnetic (EM) pulses of optical and terahertz ranges is investigated under the three-wave interaction with the space charge wave (SCW) in n-GaN films. SCW is amplified due to the negative differential conductivity at the frequencies f ≤ 500 GHz. The three-wave resonant interaction of two counterpropagating EM waves with SCW is considered in the waveguides...
The design of CMOS RF power amplifiers is reviewed. Design consideration for RF and mm-wave frequencies are given for output power, gain, efficiency, linearity and stability. Recent circuit design trends on both the architectural and circuit level are discussed.
The aim of the paper is to design an antenna suitable for wireless devices used in telemedicine, simulate and test its performance. To achieve this objective, a simpler, lighter, smaller sized fractal antenna is proposed. The antenna is designed on a FR4 substrate of size 36mm×36mm×1.6mm and is co-planar waveguide (CPW) fed. It resonates at three frequencies providing triple band operations in the...
A multiuser beam-free circular adaptive active array is considered. Such antennas can be used instead of standard multisector antennas. The multiuser beam-free method implies that coverage area is not divided into cells with different frequencies. Instead, all the users can use all the frequencies and active array selects signals by their position. The comparison of the standard multisector antennas...
Utilization of the pulses with ultra wide frequency band (UWB) in microwave imaging systems enables obtaining great resolution and simultaneously taking benefits from the microwaves' penetrating ability [4], [16]. Short duration of the pulses — which is what causes their wide frequency band — has also this advantage that it gives opportunity to perform time analysis and eliminate many unwanted signals,...
This paper deals with the parametric analysis and proper design of parabolic reflector antennas to obtain pencil-beam, cosecant-squared and inverse cosecant-squared radiation patterns for air and coastal surveillance radars. A novel design is introduced to obtain both pencil-beam and cosecant-squared radiation patterns by using the same modified parabolic reflector antenna structure fed by an H-plane...
GPR object detection is always a challenge in most practical applications. The hyperbola feature in B-Scan data is a very important feature for GPR object detection. In this paper, a novel method based on cross correlation between adjacent A-scans is proposed to detect reflection hyperbola. The method includes four steps. B-scan data is firstly preprocessed to suppress clutters. Then, the reflection...
The nonlinear interactions of space charge waves (SCW) in n-GaN films are investigated theoretically. SCW are amplified due to the negative differential conductivity. The transversely nonuniform films are considered. The hydrodynamic diffusion-drift equations for volume electron concentration were used jointly with the Poisson equation for the electric field. The transverse inhomogeneity results in...
A charge-image model was applied to solve the problem concerning the space-time formation of an electromagnetic field when the boundary between the vacuum and the perfectly conducting half-space is crossed by the point charge particle with a final velocity and acceleration. The cases of normal and oblique incidence of a charge at the boundary are under consideration. In the case of oblique incidence,...
This paper is addressed to the improvement of the range resolution of MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) by means of a modified version of the stepped frequency processing algorithm. MARSIS is a low frequency, pulse-limited radar sounder and altimeter selected by ESA as a payload of the Mars Express mission. The ionosphere affects MARSIS operation in terms of phase...
This paper introduces a novel approach for transmitting UWB signals over optical fibre with cost effective Vertical-cavity surface-emitting laser (VCSEL). The transmitted impulse compile with the strict European frequency plan (ECC). A prototype filter is presented with lumped elements which has a −40 dB/500 MHz cut off at the critical 3.1 GHz band. Also a novel impedance matching method is presented...
The requirements and the possible solutions for waveforms suited to multifunction phased array radar (MPAR) are described. A reasonable cost of the basic building block of the MPAR, i.e. for the Transmit-receive module (TRM), can only be obtained by lowering the peak power to the order of one watt by pulse-compression. Therefore, MPAR systems call for "long" transmitted signals, i.e. with...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.