ACES Publication Search
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| Title: | ACES Journal July 2025 Cover |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 1966 KB |
| Title: | ACES Journal July 2025 Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 276 KB |
| Title: | ACES Journal July 2025 Full |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 27890 KB |
| Title: | A Lossy Coated Thin Wire Model Based on the Unconditionally Stable Associated Hermite FDTD Method |
| Abstract: | This paper presents a lossy coated thin wire model based on the unconditionally stable (US) associated Hermite finite-difference time-domain (AH FDTD) method. The normal electric field discontinuity between lossy coated and surrounding media is corrected as the time-domain boundary condition. The coefficient matrix equation of lossy coated thin wires in AH domain is deduced by the static field model of infinite thin wires and the Faraday’s law contour-path formulation, finally the thin wires with lossy coated is modeled. Three examples of dipole antenna, five-element Yagi antenna and square antenna are used to verify the accuracy and high efficiency of the lossy coated thin wire model. The results show that the model can maintain the relative error of less than −26 dB and reduce computation time compared with the traditional FDTD method. |
| Author(s): | Y.-R. Zheng, S. Zheng, C. Chao, Z.-Y. Huang, X.-R. Chen |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 4976 KB |
| Title: | Iterative WCIP Approach for Modeling Zero Index Metamaterials With Lumped Materials |
| Abstract: | This paper presents a comprehensive investigation into zero-refractive index materials (ZIMs) through the application of transmission lines modeled by their inductance-capacity (L-C) representation. Using the wave concept iterative procedure (WCIP) method, the study accurately simulates the behavior of ZIMs, demonstrating their unique ability to maintain consistent phase and amplitude of electromagnetic waves across a ZIM region. Our results show that ZIMs enhance the electromagnetic directivity of a source by 30% compared to conventional materials and facilitate seamless, reflection-free transitions between waveguides of varying sections. The simulation results of the electric field E for the narrow section waveguide align closely with theoretical expectations for ZIMs, showing less than 2% deviation. These quantitative findings validate the superior performance of ZIMs in maintaining wave coherence and improving directivity. When compared to existing materials, ZIMs offer a significant improvement in transmission efficiency, with a 25% reduction in signal loss. These advancements position ZIMs as a promising solution for applications in telecommunications, radar, and wireless transmission systems, outperforming current state-of-the-art technologies. |
| Author(s): | M. K. Azizi, K. Mekki, T. Elbellili |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 441 KB |
| Title: | Ultrawideband Bowtie Slot Antenna With Defected Ground Structure |
| Abstract: | An ultrawideband (UWB) antenna is well-suited for several applications, particularly in wireless communications, radar and sensing systems. A UWB antenna covering 1.8 GHz to 3.8 GHz is proposed in this research work. A study was conducted on a bowtie slot antenna with different combinations and shapes of defected ground structure (DGS). Different shapes of DGS were introduced to investigate the effects of DGS on the bandwidth, reflection coefficient and radiation performance of the antenna. For the bowtie slot antenna with partial ground and circular DGS, there are three resonant frequencies with lowest S11 at 2.0 GHz (-18.5 dB), 2.5 GHz (-36.5 dB) and 3.3 GHz (-41.5 dB), while the antenna design with partial ground and dumbbell DGS has resonant frequencies at 2.0 GHz (-18.5 dB), 2.5 GHz (-36.5 dB) and 3.3 GHz (-44 dB). Upon adding a DGS structure such as a circle or dumbbell on the ground plane, the bandwidth performance of the proposed antenna was significantly enhanced. The radiation efficiency of the proposed antenna reached 80% and the directivity was 4.17 dBi (2.0 GHz), 5.58 dBi (2.5 GHz) and 5.18 dBi (3.3 GHz). |
| Author(s): | R. S. W. Ting, I. S. Z. Abidin, A. A. Aziz |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 1703 KB |
| Title: | Crosstalk Analysis of Multi-conductor Transmission Lines Excited by Long-time Interference Sources Based on Finite-difference Frequency-domain Method |
| Abstract: | When addressing the crosstalk problems of multi-conductor transmission lines (MTLs) excited by long-time interference sources, time-domain methods suffer from lengthy simulation duration for such scenario, while the conventional finite-difference frequency-domain (FDFD) method encounters efficiency limitations due to its requirement for direct meshing the fine structures of MTLs. Under the circumstance, a new frequency-domain hybrid method based on the FDFD method and the transmission line (TL) equations is proposed. Within this method, the crosstalk model of the MTLs is constructed depending on TL equations firstly. Then, TL equations are solved by the difference scheme of FDFD method, and the FDFD-TL matrix equation applicable for the crosstalk modeling of MTLs are derived and established. Finally, the conjugate gradient method combined with message passing interface (MPI) parallel technique is utilized to solve the FDFD-TL matrix equation and obtain the voltage responses along the MTLs and their terminal loads. Two simulation cases about the crosstalk of multi-conductor TLs excited by lumped pulse sources are calculated and compared with the Method of Moments (MoM) to verify the accuracy and efficiency of the proposed method. |
| Author(s): | Z. Ye, Y. Zhai, M. Liu |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 1601 KB |
| Title: | Low-loss Miniaturized Tri-band Bandpass Filter with High Selectivity and Good Passband Symmetry |
| Abstract: | This paper introduces a low-loss microstrip line tri-band bandpass filter, utilizing quarter-wavelength (λg/4) tri-section stepped impedance resonators (TSSIRs). In this design, the adoption of a non-edge-coupled structure effectively eliminates the presence of coupling gaps. As a result, additional radiation losses are avoided, leading to lower insertion loss. In addition, the operating frequencies of the three passbands can be flexibly adjusted by tuning the impedance ratios in the TSSIR. Moreover, the λg/4 TSSIR exhibits a smaller size compared to existing λg/2 TSSIRs, resulting in a more compact overall design. In order to validate the proposed design methodology, a tri-band bandpass filter with passbands centered at 1.0 GHz, 3.5 GHz, and 6.0 GHz was designed, fabricated, and measured. The minimum insertion losses for each passband were measured to be 0.07 dB, 0.52 dB, and 1.14 dB, respectively. The filter occupies a compact area of 31×21.5 mm2 (0.17λg×0.12λg), demonstrating excellent passband symmetry for each frequency band. The proposed tri-band bandpass filter not only achieves three desirable operating frequencies but also benefits from the inherent characteristics of conventional filters, such as remarkably low insertion loss and good passband symmetry |
| Author(s): | C. Shao |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 617 KB |
| Title: | Compact Bandpass Filter for Ultra-wide Stopband Rejection |
| Abstract: | The design objectives for a bandpass filter intended for modern wireless applications include achieving wide stopband attenuation and preserving signal strength within the passband. The proposed architecture aims to provide an effective solution for WLAN systems by minimizing insertion loss while sustaining other essential performance parameters. An asymmetric-short to the stepped impedance resonator (ASSIR) band-pass filter is presented. The second-order end coupled filter is initially designed, and transmission zeros and resonance frequencies are mathematically derived using ABCD parameters and odd and even mode calculations, respectively. A middle-short is introduced to the resonators to increase the depth of transmission zeros at the band edges. Further, an asymmetric-short to the resonators, along with stubs at the feed lines, is incorporated to realize an ultrawide stopband until 12.8 GHz and also to achieve compactness of 0.3λg×0.18λg without modifying the structure. The low-cost FR4 substrate εr = 4.4, simple end-coupled ASSIR bandpass filters is mathematically verified, simulated and measured at 2.45 GHz with an in-band low insertion loss of 1.4 dB. |
| Author(s): | P. Narayanan, M. Shanmugam |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 1077 KB |
| Title: | Analysis of an Oil-Spray Cooling System for an Induction Switched Reluctance Machine Using Computational Fluid Dynamics |
| Abstract: | The growing interest in electric vehicles has spurred the development of high-performance electric machines. The effective cooling of windings in electric machines is essential as they are the primary site of energy loss. Oil-spray cooling systems have gained popularity due to their ability to reduce temperatures and protect winding insulation. This paper proposes a Computational Fluid Dynamics (CFD) model for the Spray-Cooling Induction Switched Reluctance Machine (ISRM) to enhance the thermal management of electric machines using Ansys Fluent software. The proposed machine demonstrates efficient heat dissipation during transient simulation tests. Oil is applied to both the stator and the rotor during a transient two-phase simulation, enabling effective thermal exchange despite uneven temperature distributions across the components. We first modeled the machine using the finite element method and extracted the losses from ANSYS. This analysis focuses on the energy losses related to the selective oil spray at the end of the rotor. By performing a detailed thermal analysis, we found that increasing the flow rate enhances the Nusselt number, improves heat transfer, and increases the machine losses. |
| Author(s): | N. Ghandi, H. Saghafi, M. Abbasian |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 917 KB |
| Title: | Wideband Circularly Polarized Metasurface Antenna with Embedded |
| Abstract: | To address the critical limitations of traditional planar antennas, such as susceptibility to carrier platform curvature and narrow bandwidth which hinder integration on complex surfaces, this paper presents a metasurface (MS) based wideband circularly polarized conformal antenna specifically designed for multi-curvature platforms. The design incorporates a systematic three-stage approach. Initially, an oblique elliptical slot-fed antenna is designed to excite orthogonal TM0 modes through slot inclination adjustment, though its axial ratio (AR) minimum fails to surpass the 3 dB threshold. To effectively improve the bandwidth, a 6×6 periodically arranged circular ring-shaped MS superstrate is incorporated, inducing new resonances that merge to form a wideband response (impedance band-width 4.1-7.5 GHz, 3 dB AR bandwidth 4.97-7.44 GHz, peak gain 7.45 dBic at 7.1 GHz). To further optimize high-frequency performance and enhance mid-band integration, a centrally offset rectangular patch embedded between the MS and slot layers, separated by an air cavity, introduces multi-mode resonance at higher frequencies, expanding the 3 dB AR bandwidth by 15% to 4-7.5 GHz. Crucially, mechanical bending tests across curvature radii of 20-50 mm reveal minimal performance fluctuations (AR fluctuation<8.3%, gain drop≤1.5 dB per 10 mm reduction in radius), demonstrating exceptional structural stability essential for conformal applications. Experimental validation confirms close agreement between simulated and measured results. This antenna achieves a compelling combination of wideband circular polarization, stable gain, low profile (0.05λ0), and robust multi-curvature conformal capability, holding significant potential for seamless integration with complex-shaped carrier platforms like curved satellite panels, UAVs, or conformal radars. |
| Author(s): | Q. Chen, J. Yang, C. He, L. Hong, F. Yu, D. Zhang, L. Zhang, M. Huang |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 11220 KB |
| Title: | FEM Simulation of Severe Stator Winding Inter-turn Short Circuit Faults of Outer Rotor DFIG |
| Abstract: | Recently, in wind power generation, doubly-fed induction generators (DFIG) have been commonly employed, and their capacity is also increasing, making DFIG’s security and reliability more significant. Stator winding inter-turn short-circuit faults (SWITSCF) are a prevalent flaw of theirs. In this paper, a DFIG has been modeled by the finite element method (FEM) in the healthy state and in the faulty state. Several simulations have been carried out for different number of inter turn short-circuit faults (NSWITSCF) to see their effects on the DFIG performance. SWITSCF modifies the impedance, which affects the current amplitudes and phases. As a consequence, the current is asymmetric where a negative sequence component is observed. SWITSCF gives the cause of the existence of the short-circuit current that generates an additional magnetic field. This will make the magnetic circuit largely saturated. Furthermore, with the NSWITSCF increasing, these negative effects appear stronger and move away from a healthy state. |
| Author(s): | H. Mellah, A. Maafa, H. Sahraoui, A. Yahiou, S. Mouassa, K. E. Hemsas |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 1963 KB |
| Title: | A Novel Compact and Lightweight Harmonic Tag for Insect Tracking |
| Abstract: | Harmonic radar sensor systems is a special wireless sensor system that has been used in insect tracking in recent years due to its excellent anti-clutter capability. Generally, a harmonic radar sensor systems consists of a radar transceiver and a specially designed harmonic tag. However, tags tend to become entangled with vegetation in insect tracking experiments. This paper proposes a strong echo signal and miniaturized low-mass passive tag design method, which targets Internet-of-Things insect tracking applications. We introduce foldable structures in antenna designing with advanced non-linear selection criterion under the unified frequency operation environment. The conversion loss (CL) of the tag is not impacted by the measures taken to minimize its mass and size. The results using both simulated and real data demonstrate remarkable improvements in size of tags, weight of tags, and echo signal strength of tags within our proposed method on the passive tags. The effectiveness of the method is verified by the results of harmonic radar illuminate tag. This work possesses the advantages of a low profile, lightweight design, strong echo signal, and compact dimensions. |
| Author(s): | Z.-F. Su, X.-R. Wan, J.-X. Yi, Z.-P. Gong, Z.-Y. Wang |
| File Type: | Journal Paper |
| Issue: | Volume: 40 Number: 7 Year: 2025 |
| Download Link: | Click here to download PDF File Size: 6473 KB |