ACES Publication Search
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| Title: | ACES Journal November 2024 Cover |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 1967 KB |
| Title: | ACES Journal November 2024 Front/Back Matter |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 256 KB |
| Title: | ACES Journal November 2024 Full |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 26496 KB |
| Title: | A Local Transition Adaptive Structured Mesh Generation Method for Finite Difference Time Domain Simulation |
| Abstract: | In this paper, a local transition adaptive structured mesh generation method is proposed for finite difference time domain (FDTD) simulation. This innovative approach can automatically identify the location of the medium interfaces and boundaries based on the triangular facet of the target, and subsequently divide the entire computational domain into numerous subregions. In the subregions, uniform mesh lines are initially placed in accordance with the numerical requirement of FDTD method. Subsequently, part of these meshes are refined based on target structure. Finally, local transition processing is performed for meshes with large variations at the boundaries of neighboring subregions, so that there is no rapid change in mesh size in the boundary position. Different from the existing automatic nonuniform mesh generation methods, the method proposed only adds transition meshes at the medium interfaces and boundaries instead of placing global gradient meshes, so it can greatly reduce the mesh quantity and simplify the mesh generation process. Two classical models of inverted-F antenna and cross-slot frequency selective surface are employed as examples to verify the validity of our method. Simulation results demonstrate that this generation method can achieve nearly equivalent simulation accuracy as the global gradient mesh generation method with a markedly reduced number of meshes. |
| Author(s): | Z. Cao, C. Mou, C. Wang, J. Chen, S. Li, C. Zhao, Y. Yin |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 2117 KB |
| Title: | Introduction of Incidence Wave using Generalized TF/SF for FDTD Analysis of Layered Media |
| Abstract: | In scattering analysis of layered media using the finite-difference time-domain (FDTD) method, conventional total-field/scattered-field (TF/SF) technique cannot inject the plane wave source. To overcome this limitation, this paper extends a generalized TF/SF (G-TF/SF) technique that embeds the TF/SF boundary within the convolutional perfectly matched layer (CPML), thus facilitating the handling of 3D electromagnetic scattering from layered media. The G-TF/SF method effectively mitigates edge effects in numerical calculations for infinite layered media. Numerical simulations validate the effectiveness of the G-TF/SF method. The method is expected to be helpful in scattering models of rough surfaces. |
| Author(s): | C. Yang, H. Xie, H. Qiao, X. Zhai, Z. Chen, Y. Gao |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 884 KB |
| Title: | Time-domain Hybrid Method for the Coupling Analysis of Curved Power Lines Illuminated by Early-time High-altitude Electromagnetic Pulse |
| Abstract: | An efficient time-domain field-to-line hybrid method is presented to realize the rapid coupling calculation of curved power lines (CPLs) illuminated by Early- Time (E1) high-altitude electromagnetic pulse (HEMP). Firstly, improved transmission line equations are derived by ideal conductor boundary conditions and transmission line theory, which are employed to construct the E1 HEMP coupling model of CPLs. Then, based on the image principle, a rapid calculation method for the excitation fields of CPLs is investigated, and improved transmission line equations are solved by the finitedifference time-domain (FDTD) method to achieve fast iterative calculation of voltage and current responses along CPLs. Finally, relevant numerical simulations are utilized to verify the accuracy and efficiency of the proposed method. On this basis, the impact of power line lengths, heights, and ground electromagnetic parameters on E1 HEMP coupling of CPLs is analyzed. |
| Author(s): | Z. Ye, Z. Gao, G. Hong, C. Tong, Z. Ji, Z. Xiao |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 1695 KB |
| Title: | A Dual-input Electromagnetic Inverse Scattering Algorithm Based on Improved U-net |
| Abstract: | In this paper, we propose a dual-input inversion method based on deep learning to improve the accuracy of electromagnetic imaging using the back propagation algorithm (BP). An improved U-Net network is utilized to reconstruct the scatterers. Unlike other deep learning inversion methods, we input both the scatterer distribution data from BP imaging and the scattered field data received by the antennas into the neural network for training. This approach leads to a more accurate prediction of scatterer positions and characteristics. Compared to predicting the scatterers using only the scattered field as input, adding the BP imaging results at the input provides the neural network with more information, significantly reduces the learning difficulty, minimizes errors, and enhances the quality of imaging. To address potential gradient vanishing and spatial information loss during network training, we integrate attention mechanisms and residual modules into the basic U-Net network. The former helps the network extract important relevant information under different contrast conditions, while the latter focuses on solving the problems of gradient vanishing and explosion. Simulation experiments confirm that our dual-input inversion method significantly reduces the average error, outperforming traditional single-input reconstruction methods. |
| Author(s): | C. X. Yang, J. J. Meng, S. Wei, M. S. Tong |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 1675 KB |
| Title: | Accelerated Extraction of Parasitic Capacitance in Metal Interconnects using Floating Random Walk Method |
| Abstract: | This paper presents a novel and efficient approach for the rapid extraction of parasitic capacitance in metal interconnects of large-scale integrated circuit (IC) layouts. By conducting detailed electromagnetic field simulations, we propose a streamlined method that significantly reduces both computational complexity and runtime, making the extraction process more efficient. At the heart of this approach is the use of the floating random walk (FRW) algorithm, which precisely estimates both self-capacitance and mutual capacitance of conductors. A distinguishing feature of this method is the incorporation of error thresholds, which provide a dynamic mechanism to adjust the trade-off between extraction speed and accuracy. This flexibility allows the method to adapt to varying layout complexities while maintaining a high level of precision. Experimental results reveal that, compared to traditional electromagnetic simulation tools such as ANSYS Maxwell, the proposed method achieves up to 120 times faster capacitance extraction, with accuracy deviations contained within 20%. |
| Author(s): | D. Zhao, Y. Chen, F. Liu, Y. Zhao, Y. Shao, D. Zhang, Y. Pan, X. Meng |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 1589 KB |
| Title: | A Wideband High Front-to-Back Ratio Directional Filtering Slot Antenna and its Application in MIMO Terminals |
| Abstract: | In this paper, a directional filtering slot antenna with a wideband high front-to-back (F/B) ratio is proposed, which aims to improve the anti-interference capability of the unit antenna in the spatial and frequency domains and reduce the coupling between MIMO units. The fundamental structure of this antenna is a transformed defective ground slot antenna, featuring superior filtering attributes in the frequency domain. To achieve a wideband F/B, boost the directional characteristics, and further augment the anti-interference capabilities of the filtering slot antenna, the leading terminal and slot are, respectively, integrated into the filtering antenna. A 2×2 MIMO antenna ensemble is also designed, utilizing the directional filtering slot antenna as the element. This antenna not only exhibits commendable filtering proficiency across the frequency and spatial domains but also effectively inhibits the surface wave and space wave coupling between MIMO antenna units. The simulated and measured results show that the operating bandwidth of the directional filtering slot antenna is 2.8-11.3 GHz, the F/B of the radiation pattern is larger than 15 dB, and the isolation between the 2×2 MIMO antenna units is greater than 20 dB without any decoupling structure. |
| Author(s): | H. Yang, H. Liu, X. Li, Y. Li, S. Wang, J. Zhang, C. Wang, Y. Fang |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 1929 KB |
| Title: | A Transparent Ultra-wideband Antenna Fed by CPW Based on Characteristic Mode Theory |
| Abstract: | This paper proposes a high isolation transparent ultra-wideband (UWB) multiple-input multipleoutput (MIMO) antenna based on characteristic mode theory. The antenna consists of four coplanar waveguide (CPW)-fed UWB monopoles, each of which is hollowed out into a mesh structure guided by feature mode theory with metal and substrates, with an excitation added at the feed point to successfully excite modes 1, 3, 5, and 7. These excited modes cover a frequency range of 1.7-13 GHz. An orthogonal layout is adopted to make the antenna structure more compact. Ultimately, a transparency of 76.3% and a radiation efficiency of over 85% are achieved, with an effective frequency band coverage of 1.32-12.15 GHz. A fan-shaped metal mesh (MM) decoupling structure is printed on the mesh structure of the antenna substrate, achieving isolation greater than 20 dB between any two components without reducing the antenna’s transparency. Across the entire operating frequency band, the gain of the antenna varies from 1.3 to 5.5 dBi within the effective bandwidth, and the envelope correlation coefficient (ECC) is less than 0.001. Additionally, the antenna exhibits good radiation characteristics. It can be easily manufactured at a low cost using traditional printed circuit board (PCB) and laser cutting techniques. |
| Author(s): | W. Ren, Z. Wang, W. Nie, W. Mu, C. Li, M. Wang |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 3660 KB |
| Title: | Butler Matrix Components Based on Substrate Integrated Waveguide Fed by Microstrip Separation Feedline for 5G Application |
| Abstract: | This paper presents a beamforming component based on vias variation substrate integrated waveguide (SIW) method at Ka-band. At Ka-band, the losses are high when planar structures are implemented due to the small wavelength, beside the expected losses from the component’s losses. Therefore, SIW technology with vias manipulation is introduced. This work aims to present a low loss coupler, crossover, and phase shifter for beamforming based on SIW at 26 GHz. Coupler and crossover are designed with vias variation based on the metallic fill inside the vias microstrip separation feedline, used for input and output ports to achieve enough distance between each adjacent port, and compact design with loss phase error. The proposed designs are simulated using CST software and fabricated using Rogers 5880 substrate with thickness of 0.508 mm and permittivity of 2.2. The measured performance agreed well with the simulated results. A return loss of less than −20 dB is achieved over a bandwidth of 5 GHz. A perfect −3 dB and 0 dB are obtained at coupler and crossover outputs. The measured phase difference −88.8° is observed at the outputs. Overall, the coupler and crossover show |
| Author(s): | Y. M. Hussein, N. A. Murad, M. K. A. Rahim, H. O. Hanoosh |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 2129 KB |
| Title: | Optimization of Receiver Optics for Radio Astronomy |
| Abstract: | In a radio telescope, the sub-reflector is illuminated by a complex feed system, consisting of a feed horn and a pair of optics focusing elements which are usually a pair of mirrors. Although rigorous analysis of this system can be performed using Method of Moments (MoM) or physical optics (POs), design optimization using these methods may not be viable, since it requires lengthy computational time. In this paper, we describe an efficient optimization technique for the optics design which applies the quadratic on a pedestal distribution to compute the taper and aperture efficiencies. In our method, multimode Gaussian optics is employed to calculate the electromagnetic waves which scatter through the optical system. The edge taper associated with the optimum aperture efficiency is first identified. By setting the parameters of this edge taper and also the distance between mirror 2 and the antenna focus as the iteration targets, a root-searching routine is then applied to determine the distances of the optical paths between the mirrors and the feed. When an optimized feed design is established, the antenna performance indicators, such as the beam efficiency, co- and cross-polarization levels, and aperture efficiencies, are calculated using PO. In this way, we combine the accuracy of the quadratic function in determining the antenna efficiencies and the computational efficiency of Gaussian optics to optimize the design of the system with the rigor of PO to validate the final parameters of the antenna. The design procedure for the Atacama Large Millimeter/Submillimeter Array (ALMA) interferometric radio telescope’s feed optics system is used as an illustrative example. The results show that the co-polar beam efficiencies achieved with the proposed method are higher than those of the original method used for the ALMA feed optics system, while the cross-polar beam efficiencies are lower. This suggests a substantial improvement offered by the new approach. |
| Author(s): | K. H. Yeap, M. C. Loh, P. C. Teh, V. Dakulagi |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 723 KB |
| Title: | Optimizing Multi-coil Integrated High-speed On/Off Valves for Enhanced Dynamic Performance with Voltage Control Strategies |
| Abstract: | In optimizing high-speed on/off valves (HSVs), key components of digital hydraulic systems, this study introduces a method designed for multi-coil integrated HSVs, differing from the traditional focus on single-coil solenoid configurations. The proposed method is an optimization framework that matches with voltage control strategies to significantly enhance the dynamic performance of HSVs. Through the integration of simulation and experimental analyses, the investigation explores the functional relationship among coil volume, temperature rise, and input power. Additionally, utilizing multi-objective optimization (MOO) techniques to improve coil design and optimize performance based on meta-model of optimal prognosis (MOP) and evolution algorithm (EA), the results demonstrate that, when employing a three-voltage control strategy, coils designed with this strategy, compared to those with a single-voltage control strategy, significantly reduce the opening time for normally closed (NC) and normally open (NO) valves by up to 40% (from 5.0 ms to 3.0 ms) and 36.4% (from 5.5 ms to 3.5 ms). |
| Author(s): | S. Huang, H. Zhou |
| File Type: | Journal Paper |
| Issue: | Volume: 39 Number: 11 Year: 2024 |
| Download Link: | Click here to download PDF File Size: 9965 KB |