2020/2

Browse

Recent Submissions

Now showing 1 - 5 of 16
  • Thumbnail Image
    Item
    Theoretical Investigations on CPW-Fed Single and Dual-Polarized Slot Radiators Using Schelkunoff’s Biconical Antenna Analysis
    (Společnost pro radioelektronické inženýrství, 2020-06) Banerjee, Amartya; Patra, Kaushik; Chatterjee, Sayan; Gupta, Bhaskar; Bandyopadhyay, Anup Kumar
    This article presents a closed-form analysis of CPW-fed slot dipole structures with the help of Schelkunoff’s biconical antenna analysis technique and Babinet’s principle. Input characteristics of CPW-fed slot dipole antennas are investigated, and closed-form expressions are derived for the purpose. The feed-gap inherently generated in CPW-fed antenna configurations is accounted for in the expressions, and the analysis of Schelkunoff is modified to address the same. Single-polarized structures can be orthogonally placed to generate dual-polarized characteristics – this notion is utilized to extend the proposed structure of a single CPW-fed slot dipole radiator towards a dual-polarized configuration. The proposed theoretical expressions are further validated for the dual-polarized geometry, and good agreement is observed in concerned theoretical and measured results. The simplicity of the proposed expressions is evident as they entirely consist of Sine and Cosine integrals and facilitate faster computation. Schelkunoff’s Biconical Antenna method is rarely used for solving a planar slot radiator problem which justifies the novelty of this article. The present work also, for the first time – modifies the method of Schelkunoff to further account for the inherently generated feed-gap in CPW-fed planar monopole or dipole configurations.
  • Thumbnail Image
    Item
    Novel Bayesian Track-Before-Detection for Drones Based VB-Multi-Bernoulli Filter and a GIGM Implementation
    (Společnost pro radioelektronické inženýrství, 2020-06) Salim, Ibrahim M.; Barbary, Mohamed; Abd Elazeem, Mohamed H.
    Joint detection and tracking of drones is a challenging radar technology; especially estimating their states with unknown measurement variances. The Bayesian track-before-detect (TBD) approach is an efficient way to detect low observable targets. In this paper, we proposed a new variational Bayesian (VB)-TBD technique for drones based on Multi-Bernoulli filter, which implemented with unknown measurement variances. Current implementation includes an analytical Gaussian inverse Gamma mixtures solution, which applied to estimate augmented kinematic drones state under the same circumstance. The results demonstrate that the proposed filter is more accurate than other Multi-Bernoulli filters in cardinality estimation. The proposed algorithm estimates the fluctuated parameters for each drone and it has no difficulty in handling the crossing of multiple drones. The Optimal Subpattern Assignment (OSPA) distances of proposed algorithm under different SNR is less than the other filters. It can be seen that at SNR (-5dB), the proposed algorithm and the other filters settle to errors 51m, 125m and 200m, respectively.
  • Thumbnail Image
    Item
    Speech Emotion Recognition using Unsupervised Feature Selection Algorithms
    (Společnost pro radioelektronické inženýrství, 2020-06) Bandela, Surekha Reddy; Kumar, T. Kishore
    The use of the combination of different speech features is a common practice to improve the accuracy of Speech Emotion Recognition (SER). Sometimes, this leads to an abrupt increase in the processing time and some of these features contribute less to emotion recognition often resulting in an incorrect prediction of emotion with which the accuracy of the SER system decreases substantially. Hence, there is a need to select the appropriate feature set that can contribute significantly to emotion recognition. This paper presents the use of Feature Selection with Adaptive Structure Learning (FSASL) and Unsupervised Feature Selection with Ordinal Locality (UFSOL) algorithms for feature dimension reduction. A novel Subset Feature Selection (SuFS) algorithm is proposed to further reduce the feature dimension and achieve a comparable better accuracy when used along with the FSASL and UFSOL algorithms. 1582 INTERSPEECH 2010 Paralinguistic, 20 Gammatone Cepstral Coefficients and Support Vector Machine classifier with 10-Fold Cross-Validation and Hold-Out Validation are considered in this work. The EMO-DB and IEMOCAP databases are used to evaluate the performance of the proposed SER system in terms of Classification accuracy and Computational Time. From the result analysis, it is evident that the proposed SER system outperforms the existing ones.
  • Thumbnail Image
    Item
    Suppressing the Effect of Impulsive Noise on Millimeter-Wave Communications Systems
    (Společnost pro radioelektronické inženýrství, 2020-06) Shhab, Lara; Rizaner, Ahmet; Ulusoy, Ali Hakan; Amca, Hasan
    The Fifth Generation (5G) wireless communication systems are expected to satisfy higher data rates, network scalability, increasing number of connections and higher traffic densities in a cost-effective manner. The key essence of 5G technology resides in exploring the frequency bands at millimeter-Wave (mmWave) frequencies. As is well known, the presence of Impulsive Noise (IN) corrupts signals and leads to increased Bit Error Rate (BER) and decreased spectral efficiency. In this paper, the performance of mmWave systems in multi-path fading channel and IN is studied and a new thresholding mechanism for the clipping and blanking filters to suppress the impulsive components of noise is suggested. The paper also presents the mathematical expressions to determine the optimum threshold selection for the filters. Simulation results show that use of clipping and blanking filters with the optimal threshold values reduces the adverse effect of IN and improves system performance significantly.
  • Thumbnail Image
    Item
    A Multi-Reconfigurable CLL-Loaded Planar Monopole Antenna
    (Společnost pro radioelektronické inženýrství, 2020-06) Fakharian, Mohammad M.; Rezaei, Pejman; Orouji, Ali A.
    In this paper, multi-reconfiguration capabilities of a planar monopole antenna with two switchable capacitively loaded loops (CLLs), as near field resonant parasitic elements, are introduced. The idea is to apply the CLLs not only to minimize the dimensions of the antenna, but also to present multiple resonances, which can be satisfactorily chosen by applying switches placed across six gaps of the CLLs. By changing the switched states, it is feasible to obtain different reconfigurations such as frequency agility (from 1.5 to 2.9 GHz), polarization diversity (with circular polarization bandwidth from 1.59 to 1.72 GHz), and various shapes of the radiation patterns and beam directions (change in the ±30° y-direction) of the antenna. The transmutation of polarization designs from their linear counterparts to left hand and right hand circular polarizations by introducing an asymmetry in the configuration of the two-CLLs is also represented. The prototypes of the proposed antenna are fabricated and tested. The measured reflection coefficient, radiation pattern, gain and axial ratio results are presented and compared to the corresponding simulated values.