ACES Publication Search
There are 23 search results for:
| Title: | ACES Journal December 2019 Cover |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2217 KB |
| Title: | ACES Journal December 2019 Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 828 KB |
| Title: | ACES Journal December 2019 Full |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 20321 KB |
| Title: | A Fast Gridless Sparse Method for Robust DOA Estimation in the Presence of Gain-phase Errors |
| Abstract: | A new gridless sparse method (GLSM) is proposed to estimate the direction of arrival (DOA) and gain-phase errors simultaneously for a uniform linear array (ULA). We convert angular space to frequency space and establish a data model in the frequency domain. First, the cost function based on the covariance fitting criterion is transformed into a semidefinite programming (SDP) problem to estimate DOA and noise variance without previous calibration information. Second, gain errors are calculated by the estimated noise variance and the covariance matrix. Third, phase errors are obtained by decomposition of the covariance matrix, which has been pre-processed by a space smoothing technique. Finally, DOA estimation is improved further after the array errors are fully calibrated. Compared with traditional methods, the proposed method is robust to correlations of signal sources, and parameters are estimated without joint iteration. Moreover, there is no need for discrete grid points in the angular space, which results in grid mismatches and computation loads, so the proposed method is more accurate and faster. Simulation results verify the effectiveness of the proposed method. |
| Author(s): | W. Peng, C. Guo, M. Wang, Y. Gao, X. Zhao |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2010 KB |
| Title: | A p-norm-like Constraint LMS Algorithm for Sparse Adaptive Beamforming |
| Abstract: | In this paper, a p-norm-like constraint normalized least mean square (PNL-CNLMS) algorithm is proposed for sparse adaptive beamforming. The proposed PNL-CNLMS algorithm inherits the good capacity of the conventional constrained least mean square (CLMS) algorithm in adaptive beamforming, i.e., forming ideal beam patterns. Also, the proposed PNL-CNLMS algorithm utilizes a p-norm-like constraint to exploit sparse property of the corresponding antenna array. In the derivation procedure, the Lagrange multiplier approach and the gradient descent method are utilized to obtain the devised updating equation. Numerical simulations reveal the superiority of the proposed PNL-CNLMS algorithm. |
| Author(s): | W. Shi, Y. Li |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1657 KB |
| Title: | Efficient Wideband MRCS Simulation for Radar HRRP Target Recognition Based on MSIB and PCA |
| Abstract: | In this paper, efficient wideband monostatic radar cross-section (MRCS) simulation is presented for radar high range resolution profile (HRRP) target recognition. Firstly, an efficient numerical approach is proposed for the wideband MRCS. The well-conditioned integral equation and the higher-order hierarchical divergence-conforming vector basis functions are utilized for the scattering field. The adaptive cross approximation (ACA) based matrix compression method is applied for efficient analysis of MRCS at a specific frequency point. The geometric theory of diffraction (GTD) based scattering model is utilized for MRCS over a wide frequency band. Secondly, the radar HRRP target identification is performed by using principal component analysis (PCA) on modified surrounding-line integral bispectrum (MSIB). The HRRP of target can be obtained by inverse fast Fourier transform (IFFT) of the spectral domain backscattering field within a certain frequency range. The one-dimensional MSIB features of HRRP are extracted to constitute eigenvectors for radar target recognition. To enhance the separation ability of radar target recognition, the MSIB is projected onto PCA space before recognition. Numerical examples prove that the proposed algorithm is feasible and efficient. |
| Author(s): | Y. Hu, T. Wan |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1854 KB |
| Title: | Novel Reduced Matrix Equation Constructing Method Accelerates Iterative Solution of Characteristic Basis Function Method |
| Abstract: | In this paper, a new construction method of reduced matrix equation is proposed to improve the iterative solution efficiency of characteristic basis function method (CBFM). Firstly, the singular value decomposition (SVD) technique is applied to compress the incident excitations and these new excitations retained on each block after SVD are defined as the excitation basis functions (EBFs). Then, the characteristic basis functions (CBFs) of each block are solved from these EBFs. Lastly, these EBFs and CBFs are used as the testing functions and the basis functions to construct the reduction matrix equation, respectively. The diagonal sub-matrices of the reduced matrix constructed by the proposed method are all identity matrices. Thus, the condition of the reduced matrix is improved resulting in a smaller number of iterations required for the solution of the reduced matrix equation. The numerical results validate the accuracy of the proposed method. Compared with the traditional CBFM, the iterative solution efficiency of the reduced matrix equation constructed by the proposed method is significantly improved. |
| Author(s): | Z. Wang, Q. Chen, W.-Y. Nie, H. Lin |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1511 KB |
| Title: | ASM-FDTD Combine the Prony’s Method to Simulate the EMP Propagation in Tunnel |
| Abstract: | The aliasing problem in ASM-FDTD is presented in detail, to overcome the problem of the ASM-FDTD method to simulate the Electromagnetic pulse (EMP) propagation in periodic tunnel structure, the prony’s method is employed to model the time domain field of the ASM-FDTD. The solution of the aliasing problem is achieved through evaluating of the exponential models at intermediate spectral points with interpolation, and the computational resource is also saved for the later time response. The accuracy of the approach is verified by comparing the results with the MW-FDTD which is calculated by parallel computing. |
| Author(s): | Y.-F. Mao, H.-B. Wu, J.-H. Chen, X.-W. Su |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1679 KB |
| Title: | High Isolated X-Band MIMO Array Using Novel Wheel-Like Metamaterial Decoupling Structure |
| Abstract: | A compact broadband antenna array with two identical antenna elements is proposed to realize high isolation that is realized via integrating a new wheel-like meta-material structure into the closely set antenna elements. The wheel-like meta-material decoupling structure is settled between the two antenna elements to reduce the coupling from the nearby antenna element. The proposed antenna array is designed, optimized, fabricated and measured in a chamber. The achieved results verify that the developed antenna is able to provide a wide bandwidth ranging from 8 GHz to 12 GHz. Using the developed wheel-like meta-material decoupling structure, not only the designed antenna array maintains performance of MIMO array, but also the coupling is reduced to be less than -20 dB within the X-band. Therefore, the proposed antenna array is a suitable candidate for X-band MIMO radar system applications to get a high isolation between the elements. |
| Author(s): | J. Jiang, Y. Xia, Y. Li |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2048 KB |
| Title: | A Low-Profile Circularly Polarized Magnetic-Electric Dipole Antenna Array |
| Abstract: | A low-profile circularly polarized (CP) magneto-electric dipole (MED) antenna array is presented in this paper. By tilting the vertical walls of a MED with two protruded stubs being orthogonal to the horizontal patches and by using a staircase-shaped feeding strip, a wideband CP MED antenna is formed. In comparison to the conventional MED, the profile of the antenna is reduced from 0.25λc to only 0.07λc at the center frequency of the operating band. The sequentially rotated feeding (SRF) network is employed to construct a 2×2 array with enhanced 3 dB axial-ratio (AR) bandwidth. The overall size of the array is as compact as 1.33λc×1.33λc×0.07λc, and the measured results show that the usable overlapped bandwidth of the reflection coefficient |S11|< -10 dB and AR< 3 dB is 31.2%, covering 1.76 GHz to 2.41 GHz. The peak gain of the array is 12.9 dBic with the gain variation being less than 3 dB within the 1.85-2.32 GHz band, and the front-backratio (FBR) is greater than 20 dB. The proposed array is promising in the applications for portable and individual communication devices for wireless communications. |
| Author(s): | P. Zhou, M. He, W. Tian, C. Zhang |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1857 KB |
| Title: | Broadband Conformal End-fire Monopole Log-periodic Antenna Array |
| Abstract: | The paper presented a broadband conformal end-fire monopole log-periodic dipole antenna array that can cover 2GHz-18GHz and have a good end-fire radiation pattern. The proposed monopole log-periodic antenna has a simple feed network, which uses slot microstrip lines as the feed network. The monopoles are designed on both sides of the copper substrate according to certain rules. The proposed 2G-18GHz conformal monopole log-periodic antenna array that consists of a metal cylinder, antennas fixed in metal inverted cone, and twelve monopole log-periodic antenna arrays. Two types monopole log-period antenna arrays conforming to a metal cylinder consisting of 2GHz-6GHz monopole log-periodic antenna unit and 6GHz-18GHz antenna unit 30° evenly placed in a wedge-shaped groove of a metal cylinder. The measured results show that the 2GHz- 18GHz end-fire antenna array are available and have good end-fire radiation. |
| Author(s): | C. Chen, J. Zhong, Y. Tan |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2173 KB |
| Title: | A Low Mutual Coupling Two-Element MIMO Antenna with a Metamaterial Matrix Loading |
| Abstract: | A low mutual coupling two-element multiple-input multiple-output (MIMO) antenna with a loading metamaterial structure is proposed numerically and experimentally. The proposed MIMO antenna operating at 5.5 GHz consists of a two-element patch antenna array and a metamaterial structure which is to reduce the coupling between the two patch antenna elements for a small radar applications. In this design, the edge-to-edge distance between two patch elements is set to be 2 mm, which is closely installed and uses the same ground plane. The proposed metamaterial structure blocks the propagation of the electromagnetic waves from the original propagation path along the substrate. The numerical and experimental results demonstrate that the mutual coupling between the antenna elements is reduced to less than -20 dB in the operating band. |
| Author(s): | P. Xu, S. Luo, Y. Xia, T. Jiang, Y. Li |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1443 KB |
| Title: | Four-Element Planar MIMO Antenna for Indoor Communications with High Isolation |
| Abstract: | A low-profile monopole microstrip antennas with multiple-input-multiple-output (MIMO) configuration for a 4G/5G communication terminal is presented. The MIMO antenna system consists of four elements that operate in the LTE1800/2600 and GSM1800 bands. The antenna elements are mounted along the four sides of a rectangular ground plane of size 120×100 mm2. Spatial diversity technique and a modified ground plane are used to enhance isolation between elements. To mitigate the mutual coupling effect, the lower corners of the ground plane have been truncated. The measured isolation is lower than -17 dB between any two elements over the operating frequency bands. The total efficiency ranges from 69% to 83% and from 73% to 86% over LTE1800 and LTE2600 bands, respectively. The diversity performance of the measured envelope correlation coefficient (ECC) and radiation patterns meet the diversity criteria for 4/5G networks. |
| Author(s): | M. M. Morsy |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1489 KB |
| Title: | Optimization of a Dual-Band, Printed Octafilar Antenna |
| Abstract: | This paper presents several innovative techniques for the design and optimization of a dual band, octafilar helix antenna. The technical challenge of this design is how close the two bands of operation are, as well as the requirement to fit inside a radome with .07λ diameter and .33λ length. This was achieved through a novel technique of applying differing pitches and terminations to the upper and lower frequency antenna filars and then feeding them from a similar location at the base. This allowed for optimal current distribution on each of the two antenna filars. The final design produced gain greater than 0dBic at zenith across both bands of operation. The techniques discussed in this paper were seen to grow low frequency performance by as much as 2.5dBic over a typical octafilar design of the same size. |
| Author(s): | J. D. Majkowski |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2573 KB |
| Title: | Study of Bandwidth and Resonant Frequency of a Rectangular Superconducting Thin Film Patch Antenna at Temperatures near Tc |
| Abstract: | Our work presents a study of High Temperature Superconductor (HTS) Yttrium Barium Copper Oxide YBaCuO rectangular thin film. It is considered to be etched on lanthanum aluminate (LaAlO3) substrate. Results are exhibited for different values of temperature and patch thickness. Validated and compared to those in literature, these results show direct proportionality between patch thickness and both of resonant frequency and bandwidth for temperatures relatively far from the critical temperature TC. When temperature becomes very close to TC, proportionality between resonant frequency and patch thickness is maintained; but it is inverted between bandwidth and patch thickness. Bandwidth is broadened at low values of thickness, but it decreases considerably when thickness increases. |
| Author(s): | A. Belhedri, A. Messai, T. A. Denidni, B. Mekimah |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1325 KB |
| Title: | Autoencoder Based Optimization for Electromagnetics Problems |
| Abstract: | In this work a novel approach is presented for topology optimization of electromagnetic devices. In particular a surrogate model based on Deep Neural Networks with encoder-decoder architecture is introduced. A first autoencoder learns to represent the input images that describe the topology, i.e., geometry and materials. The novel idea is to use the low dimensional latent space (i.e., the output space of the encoder) as the search space of the optimization algorithm, instead of using the higher dimensional space represented by the input images. A second neural network learns the relationship between the encoder outputs and the objective function (i.e., an electromagnetic quantity that is crucial for the design of the device) which is calculated by means of a numerical analysis. The calculation time for the optimization is greatly improved by reducing the dimensionality of the search space, and by introducing the surrogate model, whereas the quality of the result is slightly affected. |
| Author(s): | S. Barmada, N. Fontana, D. Thomopulos, M. Tucci |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1524 KB |
| Title: | Characterization of Atmospheric Absorption in the 60 GHz Frequency Band Using a Multi-Pole Material Model |
| Abstract: | Atmospheric attenuation of electromagnetic signals at the 60 GHz frequency band is dominated by oxygen absorption which represents a major obstacle to 5G communications using this band. So far, only empirical equations that fit the experimental absorption data have been reported. These empirical models are not suitable to employ in standard full-wave electromagnetic simulators based on the numerical solution of Maxwell’s equations. In this paper, a frequency-dependent material model for atmospheric absorption at the 60 GHz band is presented. Further, a numerical simulator that incorporates this multi-pole material dispersion model and uses the rotating boundary conditions to allow for long propagation distances is developed. The simulation algorithm is based on the auxiliary differential equation finite-difference time-domain (ADE-FDTD) technique which implements the general electric polarization formulation. The results are useful in the prediction of propagation power loss between line-of-sight communication links and in the planning and positioning of ground and air-borne facilities. |
| Author(s): | M. Arvas, E. Arvas, M. A. Alsunaidi |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2046 KB |
| Title: | A Tunable Trisection Bandpass Filter with Constant Fractional Bandwidth Based on Magnetic Coupling |
| Abstract: | A tunable microstrip trisection bandpass filter with source-load coupling is proposed in this paper. Magnetic cross coupling structure based on varactor loaded open ring resonators is employed. No extra capacitor is used to adjust the coupling coefficients directly. Normalized coupling matrix M is used to calculate the frequency response, and formulas for computing the S parameters based on the resonator with unconventional phase performance are given. Coupling coefficients are investigated by computing the integral of the distributed voltage/current and it is proved that the coupling coefficients can meet the requirements of constant fractional bandwidth (CFBW). Due to the magnetic cross coupled trisection structure and the electrical source-load coupling, this tunable filter has three transmission zeros at finite frequency which can effectively improve the frequency selectivity. The measurement agrees well with the simulation. The center frequency can be tuned from 1097 MHz to 1936 MHz. In this tuning range, the insertion loss varies from 7.8 dB to 4 dB. A constant fractional bandwidth of about 5% is achieved. |
| Author(s): | M. Fu, Q. Xiang, Q. Feng |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1487 KB |
| Title: | An Improved E-Plane Waveguide Power Divider Design for 94GHz Dual-Pyramidal Horn Antenna |
| Abstract: | In this paper, a waveguide power divider is proposed for a 94 GHz horn antenna. The entire structure was machined using 3D printing technology, and is comprised of two pyramidal horn antennas, a one to two E-plane waveguide power divider, three waveguide bends, and a flange. By introducing a wedge-shaped groove, two trapezium taper ports, and a λg/2 extension on the T-junction of the waveguide, we found improved impedance matching of the power divider, and the two output ports had the same phase. Our results show that the bandwidth of the antenna was 3.2% (3 GHz), its gain was higher than 21.2 dBi with an approximately 10° half power beam width at 94 GHz, and it could be applied to a precise location at close range (6 m to 10 m), which is suitable for automotive radar applications. |
| Author(s): | X. Zhang, Y. Chen, Y. Xie, L. Liu |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1881 KB |
| Title: | Electric Field and SAR Distribution in the Vicinity of Orthodontic Brace Exposed to the Cell Phone Radiation |
| Abstract: | The aim of this study is to investigate the impact of orthodontic brace on the electric field distribution and amount of the absorbed energy from the cell phone within the teeth. A comparative analysis of the models (child and adult) with and without brace has been carried out due to different morphological and tissue characteristics of child’s and adult’s head. The 3D realistic models of the child’s and adult’s head, with the jaw having the orthodontic brace, have been designed. The shapes and features of the child and adult head model, as well as the distance between the electromagnetic source and the exposed object, have an important role in the evaluation of the Specific Absorption Rate (SAR). The applied procedure is based on the numerical solution of the electromagnetic waves propagation equations. The numerical analysis has been performed at the frequency of 3G (0.9GHz). The obtained results are represented within the teeth positioned on the side of the electromagnetic radiation source. Based on the obtained results, one can conclude that the presence of orthodontic brace affects the increase of electric field and SAR within the teeth. |
| Author(s): | D. B. Jovanovic, D. D. Krasic, V. B. Stankovic, N. N. Cvetkovic, D. D. Vuckovic |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2297 KB |
| Title: | Miniaturized Frequency Selective Radome Operating in the X-Band with Wideband Absorption |
| Abstract: | In this work, a miniaturized frequency selective radome with wideband absorption is presented. The proposed design consists of a bandpass FSS and a resistive FSS. Both FSS’s are combined together through a foam spacer. A slotted miniaturized form of the conventional Jerusalem cross structure is employed as the bandpass FSS. A meandered form of the basic square loop with lumped resistors incorporated in each side of the loop is used as the resistive FSS. The bandpass FSS ensures the transmission in the X-band, which is the operating band of the radome. The resistive FSS absorbs the out-of-band signals and thus reduces RCS at higher frequencies. The proposed design operates in the frequency range of 8.88-10.85 GHz and absorbs between 18.8-28.35 GHz. The insertion loss at the center frequency of the operating band is 0.82 dB. The thickness of the entire structure is 0.07 λₒ with respect to center frequency (10 GHz) of the operating band. The overall size of a unit cell of the miniaturized design is 0.2 λₒ that ensure angular stability for different polarizations and incident angles. |
| Author(s): | H. Ahmad, M.-U. Rahman, S. Bashir, W. Zaman, F. C. Seman |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1651 KB |
| Title: | Eddy Currents Induced in Two Parallel Round Conductors |
| Abstract: | The paper presents a method of analysis of eddy currents induced in a system of two parallel round conductors by a transverse alternating magnetic field generated by a current in one of them. The magnetic field is represented by means of magnetic vector potential as expansion into Fourier series. Using the Laplace and Helmholtz equations as well as the classical boundary conditions we determine analytically the current density induced due to the proximity effect. Power transmission lines with round conductors are widely used in distribution networks. Therefore, although the paper is theoretical, the determination of electromagnetic parameters of the power transmission lines is of huge practical significance. |
| Author(s): | T. Szczegielniak, P. Jablonski, D. Kusiak, Z. Piatek |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 1790 KB |
| Title: | Efficient Computational Model of Phase Noise and its Applicability to Assess the Performance of Digital Modulation Techniques |
| Abstract: | Two methods are proposed to get a discretetime model for a sinusoidal carrier signal affected by phase noise of a predetermined power spectral density (PSD). The proposed methods aim to calculate the instantaneous phase error at the discrete time samples. In the first method, uncorrelated uniformly distributed random numbers are generated at the discrete time samples and added to the angle of the carrier. These phase samples are, then, correlated along the time by enforcing the spectrum of the signal to take the magnitudes obtained from the predetermined PSD. In the second method, uniformly distributed random numbers are generated at the discrete frequencies which are uncorrelated along the frequency to represent the phase of the signal spectrum. In both methods, a subsequent application of the inverse Fourier transform results in the time domain waveform of the signal in which the time samples of the phase error appear as correlated random values. The instantaneous phase error is calculated for different ratios of the noise-to-carrier power. Experimental measurements of the PSD of the phase noise for some commercially available microwave generators are performed and the measurements are used to calculate the instantaneous phase error associating the output signal. In all the cases, the obtained phase noise model is used to study the effect of such a noise type on the performance of M-ary PSK communication systems where the dependence of the bit-error-rate on the noiseto- carrier power level is investigated. |
| Author(s): | A. E. Farahat, K. F. A. Hussein |
| File Type: | Journal Paper |
| Issue: | Volume: 34 Number: 12 Year: 2019 |
| Download Link: | Click here to download PDF File Size: 2258 KB |