Aeu-International Journal of Electronics and Communications最新文献

{"title":"Joint robust beamforming design for RIS-assisted ISAC systems with hardware impairments","authors":"Xinyu Zhang ,&nbsp;Lijuan Zhong ,&nbsp;Shidang Li ,&nbsp;Yanping Zhou ,&nbsp;Jianbin Cao ,&nbsp;Chunguo Li","doi":"10.1016/j.aeue.2026.156209","DOIUrl":"10.1016/j.aeue.2026.156209","url":null,"abstract":"<div><div>In practical wireless systems, transceiver hardware impairments (HWIs) introduce additional noise and nonlinear distortions, leading to degradation in physical layer security performance. In integrated sensing and communication (ISAC) systems, the transmitted waveform carrying communication information is susceptible to eavesdropping by sensing targets. To address this challenge, this paper investigates a reconfigurable intelligent surface (RIS)-assisted ISAC system that accounts for hardware impairments at both the transmitter and receiver. To enhance physical layer security and reduce information leakage to unauthorized users, we propose the strategic injection of artificial noise (AN) under certain conditions to degrade the signal quality at potential eavesdroppers. Specifically, we formulate a joint optimization problem involving sensing beamforming, artificial noise design, and RIS reflection coefficients, aiming to maximize the achievable secrecy rate while satisfying constraints on total transmit power, minimum communication rate, minimum radar sensing signal-to-noise ratio (SINR), and unit-modulus reflection coefficients. To solve the resulting non-convex problem, we first perform an equivalent transformation and decouple it into two non-convex subproblems. We then apply successive convex approximation (SCA) and semidefinite relaxation (SDR) to approximate the subproblems as convex programs. Finally, an alternating optimization (AO) algorithm is developed to efficiently solve the reformulated problem. Simulation results demonstrate that the proposed scheme effectively mitigates the performance degradation caused by hardware impairments and achieves an optimal trade-off between interference shaping and privacy preservation, outperforming conventional schemes without AN, RIS, or hardware impairment considerations.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156209"},"PeriodicalIF":3.2,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Broadband and compact filtering power divider employing quarter circular/cambered SIW and CPW structures","authors":"Ke-Long Sheng,&nbsp;Xiang Wang,&nbsp;Song-Song Qian,&nbsp;Zhi-Yuan Zong,&nbsp;Huangyan Li,&nbsp;Boyu Sima,&nbsp;Wen Wu","doi":"10.1016/j.aeue.2026.156196","DOIUrl":"10.1016/j.aeue.2026.156196","url":null,"abstract":"<div><div>This paper proposes a broadband and compact filtering power divider (FPD) based on quarter circular/cambered (QCC) substrate integrated waveguide (SIW) and coplanar waveguide (CPW) resonators. Firstly, the impact of the CPW slot length on the quality factor (<em>Q</em>) of the QCC SIW resonator is analyzed. Subsequently, the CPW resonator is integrated into the QCC SIW to form a third-order bandpass filter (BPF) with a cascaded trisection (CT) topology. A transmission zero is located in the upper stopband. Finally, two third-order hybrid QCC SIW and CPW filtering power dividers (FPDs) with and without isolation resistors are designed. Furthermore, this paper introduces a new method for rapidly determining the quantity and value of isolation resistors. All the designs presented in this paper are simulated, manufactured, and experimentally validated. The measured results indicate that the proposed third-order FPD with isolation resistors operates at a center frequency of 5.08 GHz with a 3-dB FBW of 41.3% (2.1 GHz). The insertion loss (IL) is approximately (3 + 1.1) dB. The isolation between two output ports is better than 16 dB. A transmission zero (TZ) can be observed at 6.75 GHz in the right side of the passband attributing to the cross-coupling scheme, which enhances the out-of-band selectivity. The overall size of the proposed FPD with isolation resistors is 1.71<em>λ</em>_<em>g</em> × 1.49<em>λ</em>_<em>g</em>, and it features advantages of broad operating bandwidth, compact physical size, and low insertion loss.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"207 ","pages":"Article 156196"},"PeriodicalIF":3.2,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compact MIMO antenna employing inductive-capacitive coupling and honeycomb defected ground structure","authors":"Trishna Doloi ,&nbsp;Gouree Shankar Das ,&nbsp;Partha Protim Kalita ,&nbsp;Yatish Beria ,&nbsp;Reeta Devi ,&nbsp;Akash Buragohain","doi":"10.1016/j.aeue.2026.156208","DOIUrl":"10.1016/j.aeue.2026.156208","url":null,"abstract":"<div><div>This work presents a fractal 2-port multiple-input multiple-output (MIMO) antenna with wideband characteristics. The design covers a frequency range of 5.2–7.8 GHz, which falls under the C-band of the electromagnetic spectrum and achieves a 40% relative bandwidth at 6.5 GHz center frequency. The antenna has a compact dimension of 28 mm × 22 mm × 1.6 mm. It consists of two planar monopole radiating elements with partial ground modifications and a sequence of parasitic slots strategically placed in the ground plane. The identical radiating patches are positioned symmetrically to reduce correlation. Inductive resonant lines are incorporated into the ground plane to work as decoupling components. This suppresses surface current coupling between the antenna ports, thereby improving isolation despite using a low-cost substrate. A honeycomb defected ground structure (DGS) layout is etched, which helps in expanding the impedance bandwidth. It provides an isolation level of more than −15 dB. The diversity parameters like channel capacity loss (CCL), mean effective gain (MEG), etc. are found to be within the optimal limits. These traits make the small wideband antenna suitable for high-performance wireless applications such as the 5.9 GHz WLAN, 5.8 GHz Wi-Fi, and Wi-Fi 6/6E (IEEE 802.11ax), among others.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156208"},"PeriodicalIF":3.2,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wideband RCS reduction of circularly polarized flexible antenna using polarization conversion metasurface","authors":"Zheng You,&nbsp;Jinqi Zhang,&nbsp;Xuyin Niu,&nbsp;Guangqian Wu,&nbsp;Shaofeng Wang","doi":"10.1016/j.aeue.2026.156206","DOIUrl":"10.1016/j.aeue.2026.156206","url":null,"abstract":"<div><div>A flexible wideband circularly polarized (CP) antenna with low radar cross section (RCS) is proposed. It employs a double-layer polarization conversion metasurface (PCM) integrated with a phase control surface (PCS). The metasurface units are orthogonally arranged to form a checkerboard patterned metasurface, which is integrated with a slot antenna array fed by a sequential rotating power divider network with a 90° phase difference. The feed network is fabricated on the flexible printed circuit (FPC). The CP antenna achieves a 3 dB axial ratio (AR) bandwidth from 6.72 GHz to 9.06 GHz and provides over 10 dB radar cross section (RCS) reduction across 5.82 GHz to 19.85 GHz. Under central bending angle from 0° to 90° conditions, the proposed antenna maintains stable RCS reduction and radiation performance, while also suppressing RCS for oblique incident electromagnetic waves within elevation angles from 0° to 45°. The designed metasurface antenna is suitable for radar detection systems and wearable devices.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156206"},"PeriodicalIF":3.2,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A partitioned iterative method for bistatic scattering analysis of PEC cavities with internal–external incident field decomposition","authors":"Da Huang,&nbsp;Ming Bai","doi":"10.1016/j.aeue.2026.156207","DOIUrl":"10.1016/j.aeue.2026.156207","url":null,"abstract":"<div><div>A partitioned iterative method is proposed for the scattering analysis of thin-walled PEC cavities under plane wave excitation. The method decomposes the excitation into internal and external components separated by the cavity aperture, enabling independent iterative calculations of induced currents on the inner and outer cavity walls. Iterative calculations for the induced currents in both parts are independent, and total scattered fields are synthesized from both parts. This partitioned iterative method is particularly applicable to solving bistatic scattering problems, achieving higher accuracy compared with the Iterative Physical Optics (IPO) method and Physical Optics (PO) in the case of cavity and duct models. Numerical results validate the accuracy of the method and the necessity of employing the partitioned iterative strategy.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156207"},"PeriodicalIF":3.2,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal modulated multi-functional Non-reciprocal filtering phase shifter with continuously tunable frequency and isolator functionalities","authors":"Girdhari Chaudhary ,&nbsp;Yongchae Jeong","doi":"10.1016/j.aeue.2025.156192","DOIUrl":"10.1016/j.aeue.2025.156192","url":null,"abstract":"<div><div>This paper presents RF co-design approach for a multi-function filtering phase shifter that integrate functionalities of a tunable bandpass filter, continuously tunable phase shifter, and isolator into a single circuit. To support detailed design, the analytical spectral S-parameters of the proposed multi-function non-reciprocal filtering phase shifter have been derived. The isolator functionality (<em>i.e.</em> |S₂₁| ≠ |S₁₂|) can be achieved using time-varying capacitors modulated by progressive phase shift sinusoidal signal. The frequency and transmission phase can be simultaneously tuned by varying resonant frequency of resonators. For experimental validation, a microstrip line multi-function non-reciprocal filtering phase shifter is designed, fabricated and measured. The measurement demonstrates a phase shift range of 200^o with forward insertion loss less than 4.9 dB and reverse isolation higher than 30 dB across all phase shift and frequency tuning states. The passband frequency is tuned from 1.42 GHz to 1.75 GHz, providing frequency tunability range of 330 MHz (<em>i.e.</em> tuning ratio: 1:1.2324), while maintaining phase shift range of 200^o at each frequency tuning state. Furthermore, the measured input and output return losses are higher than 12 dB for each phase shift and passband frequency tuning states.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156192"},"PeriodicalIF":3.2,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Behavioral modeling of microwave components in constrained domains using recurrent neural networks with attention layers","authors":"Slawomir Koziel ,&nbsp;Kaustab C. Sahu ,&nbsp;Anna Pietrenko-Dabrowska","doi":"10.1016/j.aeue.2025.156193","DOIUrl":"10.1016/j.aeue.2025.156193","url":null,"abstract":"<div><div>Full-wave electromagnetic (EM) analysis is commonly used in microwave engineering. Nonetheless, EM-driven design involves considerable expenses. Surrogate modeling may mitigate this issue; however, constructing reliable metamodels is demanding due to the curse of dimensionality and design utility requirements. This paper introduces a novel data-driven modeling methodology that integrates an attention mechanism into Recurrent Neural Networks (RNNs) based on Long Short-Term Memory (LSTM) and Gated Recurrent Units (GRU). The proposed surrogate enhances the representation of sequential dependencies across the frequency range in S-parameter estimation, treating frequency responses as time-series data. The projected LSTM and GRU layers reduce the dimensionality of the hidden states through a learned projection matrix, which reduces computational complexity and enhances the capacity of the model to capture long-term dependencies. Another enhancement is the attention mechanism, which dynamically assigns greater importance to critical frequency regions and enables the model to selectively highlight the most relevant components (e.g., corresponding to the circuit's center frequencies). The predictive power is further improved by sensitivity-based dimensionality reduction. Comprehensive verification showcases the competitive performance of our technique regarding predictive power as compared to multiple benchmark methods.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156193"},"PeriodicalIF":3.2,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive neuro fuzzy control of a high gain bidirectional power converter for photovoltaic-hydrogen renewable electric vehicles with enhanced lifespan and reliability","authors":"Davut Ertekin ,&nbsp;Mustafa Özden","doi":"10.1016/j.aeue.2026.156198","DOIUrl":"10.1016/j.aeue.2026.156198","url":null,"abstract":"<div><div>The demand for green energy and application of hydrogen or photovoltaic (PV) for electrical vehicles (EVs) are enhancing steadily each day. DC–DC converters are critical power conversion systems that regulate voltage and current levels for battery packs in electric vehicles (EVs) powered by fuel cells (FCs) or PV panels and set the voltage for electric motor through an inverter circuit. The longevity of renewable energy sources (RESs) such as the FCs and PV arrays is heavily influenced by the current drawn by the DC–DC converter. Additionally, the converter topology must be cost-effective, minimize voltage and current stresses on semiconductor devices, offer ease of control, and provide flexible voltage outputs to meet the dynamic demands of the battery pack. This study introduces a switching DC–DC power converter designed specifically for FC-based electric vehicles (FCEVs), controlled by an innovative adaptive neuro fuzzy controller (ANFC). The high gain of the proposed converter enables the energy obtained from FCs and PV cells to be stored in a high-voltage battery pack and subsequently used to drive the electric motor and other electric vehicle components (such as lighting, heating, or cooling). This implies that, in an electric vehicle, it is sufficient to use only the proposed power converter instead of employing separate DC–DC converters for different energy sources such as PV or FCs. Subsequently, the stored energy can be used to operate the motor by providing the input voltage to the inverter. This approach makes the overall system more efficient and cost-effective. At the end of the simulation studies, it was observed that the proposed controller successfully ensures the control of the DC–DC converter, that no overshoot or oscillation occurs at the converter output, that an extremely short settling time of 0.016 s is achieved, and that a very low steady-state error of 0.7 is obtained. Experimental results for the proposed power converter are presented, thereby validating the theoretical findings.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156198"},"PeriodicalIF":3.2,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving an Indoor RIS Surface Location via the Motley-Keenan Model and a Two-Stage Grid Search Algorithm","authors":"Basma Nazar,&nbsp;Sarab Kamal Mahmood,&nbsp;Noor Aldeen Hamza","doi":"10.1016/j.aeue.2025.156194","DOIUrl":"10.1016/j.aeue.2025.156194","url":null,"abstract":"<div><div>Employing a Reconfigurable Intelligent Surface (RIS) in indoor environments is a promising technology for enhancing the quality of communication among multiple Internet of Things (IoT) devices, particularly when barriers within structures obstruct direct pathways between network components and the receiving end. Selecting the optimal placement for installing the RIS within a building profoundly influences transmission quality and network coverage, particularly when devices are situated at considerable distances or have to pass several obstacles before their signal reaches the receiver. In this paper, we propose three distinct approaches to determining the optimal site for the RIS, which will be installed on the ceiling of the building. This ensures comprehensive coverage for all network components transmitting data to the Base Station (BS) in uplink mode via Wi-Fi. All three methods depend on calculating the <span><math><msup><mn>5</mn><mi>th</mi></msup></math></span> percentile of the lowest Signal-to-Noise ratio (SNR) values for IoT devices by utilizing the Hyndman-Fan Type 7 approach and the balance paths losses for the second and third methods to find the optimal site for the RIS surface. Additionally, our research's propagation model utilizes the Motley-Keenan model to determine route losses. Also, the RIS's losses, encompassing phase quantization and orientation losses, are considered in its total gain. A two-stage search methodology, including a coarse search succeeded by a fine search, was employed to ascertain the optimal location for the RIS. Furthermore, in this research, we employed two geometric representations of the indoor environment: the two-dimensional (2D) and three-dimensional (3D) representations, in addition to two different modulation schemes (QPSK and 16QAM) for each method.The present research also presumes perfect large-scale channel state information (CSI) for the IoT-RIS and RIS-BS connections, as well as a static indoor layout with fixed locations of IoT devices and obstructions. Finally, the maximum (SNR) of 5 % was recorded at the designated locations, coverage was assessed during the fine search phase, and the performance measurements at the designated sites and the final RIS location for each approach across many parameters are presented in tables and figures in addition to calculate the complexity of this proposed methods.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156194"},"PeriodicalIF":3.2,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated design of irregularly shaped microstrip bandpass filters with 2-bit fragment-type structure","authors":"Gongda Hu ,&nbsp;Yukun Fang ,&nbsp;Dawei Ding","doi":"10.1016/j.aeue.2026.156197","DOIUrl":"10.1016/j.aeue.2026.156197","url":null,"abstract":"<div><div>In this article, a novel 2-bit fragment-type structure (FTS) design technique is proposed for automated design of microstrip bandpass filters (BPFs) of flexible structure and irregular shape. The 2-bit FTS description includes subtle structures in FTS elements on PCBs, which increase the dynamic range of equivalent reactance compared with 1-bit FTS without yielding large design matrix for BPF structure characterization. Structural coding method for 2-bit FTS with necessary vias is proposed, and multi-objective optimization search scheme for the FTS-based high performance BPF is illustrated. For demonstration, two compact planar BPFs with sharp roll-off are designed for operation at <em>f</em>₀ = 1.75 GHz. The one with irregular design area presents a measured 3-dB passband of 32.1 %, in-band return loss (RL) of over 23 dB, and suppression of at least 20 dB in the stopband up to 2.1 <em>f</em>₀. The mechanism of provoking multiple transmission zeros with 2-bit FTS are explained and performance comparison is conducted.</div></div>","PeriodicalId":50844,"journal":{"name":"Aeu-International Journal of Electronics and Communications","volume":"206 ","pages":"Article 156197"},"PeriodicalIF":3.2,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}