2019/3

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Design and Implementation of Fractional-Order Microwave Integrator
(Společnost pro radioelektronické inženýrství, 2019-09) Gupta, Mridul; Upadhyay, Dharmendra Kumar
A novel design of fractional-order microwave integrator using shunt connected open-stubs with transmission line sections in cascade is proposed. Design is obtained by optimizing the L1-norm based error function in Z-domain having not more than absolute magnitude error value of 0.01. Optimization is done using nature inspired cuckoo search algorithm. Superiority of the design in terms of magnitude error performance is identified by comparing it with the results obtained from some widely used benchmark optimization algorithms. The obtained design is implemented on a RT/Duroid 5880 substrate having 20 mil thickness, and results for the measured magnitude response are found to be in good agreement with ideal one over the frequency range of 1.0 GHz to 6.8 GHz.
A New Approach to OTH Main Parameters Determination
(Společnost pro radioelektronické inženýrství, 2019-09) Saavedra, Zenon; Argota, Julio N.; Cabrera, Miguel A.; Elias, Ana G.
In this work, we propose a method based on a simulation that incorporates several models to provide the set of parameters needed on Over-The-Horizon radars (OTHR) performance evaluation, which consists in a versatile software tool. Obtaining the signals involved during transmission and reception is a complex and challenging task. Among them, the received signal is fundamental to design methods and algorithms in the target detection strategy. The parameters in the transmission and reception processes that define the radio link main features are determined in terms of target type, ionospheric conditions, radio link characteristics, and other environmental properties. The determination is done combining models to work assembled in a software tool that simulates the OTHR radio link. The tool gives the possibility of step away from the linear model, which uses mainly constant parameters and it is used commonly. A large number of set up parameters and also interconnections among several models enable to simulate nearer to actual search sceneries.
The Detection Performance of the Dual-Sequence-Frequency-Hopping Signal via Stochastic Resonance Processing under Color Noise
(Společnost pro radioelektronické inženýrství, 2019-09) Liu, Guangkai; Kang, Yanmei; Quan, Houde; Sun, Huixian; Cui, Peizhang; Guo, Chao
Can the Dual-Sequence-Frequency-Hopping (DSFH) as a military emergency communication mode work under strong color noise? And is there any detection improvement of the DSFH signal via stochastic resonance (SR) processing under color noise? To deal with this problem, we analyze the physical feature of the DSFH signal. Firstly, the signal models of transmission, reception and the intermediate frequency (IF) are constructed. And the scale transaction is used to adjust the IF signal to fit the SR. Secondly, the non-markovian Langevin Equation (LE) is transformed into a markovian one by expand the 1-D LE to~a 2-D one. Thirdly, the non-autonomous Fokker-Plank Equation (FPE) is transformed into an autonomous one by assuming that the SR transition of magnetic particles is instantaneous and introducing the decision time. Therefore, the analytical periodic steady solution of the probability density function (PDF) with the parameter of the correlation time of the color noise is obtained. Finally, the detection probability, false alarm probability and Receiver Operating Characteristics (ROC) curve are obtained, under the criterion of the maximum~a posterior probability (MAP). Theoretical and simulation results show as below: 1) whether the DSFH can work under strong color noise is decided by the correlation time of the color noise; 2) when the power intensity of the color noise is constant, the smaller the correlation time with the bigger local SNR, the greater PDF difference of the SR output under two hypothesis, leading to better detection performance.
Dim Target Detection in Infrared Images Using Saliency Algorithms
(Společnost pro radioelektronické inženýrství, 2019-09) Tunc, Seyit; Ilgin, Hakki Alparslan
Infrared (IR) target detection and tracking are commonly used in modern defense systems. Target detection is the first and very important step for several surveillance applications. Long distance between imager and targets or bad weather conditions mostly cause dim target appearance with low signal-to-noise ratio (SNR) in IR images. In this study, dim targets in IR images are enhanced and detected using saliency detection algorithms, which have not been used in IR wavelength before. Performances of the algorithms are evaluated on common IR datasets. Algorithms are compared in terms of SNR, receiver operating characteristic (ROC) and area under curve (AUC) score. Effects of parameter selection are also considered for automatic target detection. Furthermore, feasibility of the methods for real-time applications are discussed.
Comparison of MOSFET Gate Waffle Patterns Based on Specific On-Resistance
(Společnost pro radioelektronické inženýrství, 2019-09) Vacula, Patrik; Kote, Vlastimil; Barri, Dalibor; Vacula, Milos; Husak, Miroslav; Jakovenko, Jiri; Privitera, Salvatore
This article describes waffle power MOSFET segmentation and defines its analytic models. Although waffle gate pattern is well-known architecture for effective channel scaling without requirements on process modification, no until today precise model considering segmentation of MOSFETs with waffle gate patterns, due to bulk connections, has been there proposed. Two different MOSFET topologies with gate waffle patterns have been investigated and compared with the same on-resistance of a standard MOSFET with finger gate pattern. The first one with diagonal metal interconnections allows reaching more than 40 % area reduction. The second MOSFET with the more simple orthogonal metal interconnections allows saving more than 20 % area. Moreover, new models defining conditions where segmented power MOSFETs with waffle gate patterns occupy less area than the standard MOSFET with finger gate pattern, have been introduced.

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