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Resonant periodic surfaces and films enable new functionalities with wide applicability in practical optical systems. Their material sparsity, ease of fabrication, and minimal interface count provide environmental and thermal stability and robustness in applications. Here, we report an experimental bandpass filter fashioned in a single patterned silicon layer on a quartz substrate. Its performance corresponds to bandpass filters requiring 15 traditional Si/SiO(2) thin-film layers. The feasibility of sparse narrowband high-efficiency bandpass filters with extremely wide, flat, and low sidebands is thereby demonstrated. This class of devices is designed with rigorous solutions of Maxwell's equations while engaging the physical principles of resonant waveguide gratings. An experimental filter presented exhibits a transmittance of ∼72%, bandwidth of ∼0.5 nm, and low sidebands spanning ∼100 nm. The proposed technology is integration-friendly and opens doors for further development in various disciplines and spectral regions where thin-film solutions are traditionally applied.
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http://dx.doi.org/10.1364/OL.40.005062 | DOI Listing |
PLoS One
September 2025
The School of Electrics and Information Engineering, Yunnan Minzu University, Kunming, China.
To address the growing demand for compact and high-performance microwave filters in modern communication systems, a mixed-mode bandpass filter is proposed in the article. A dual-layer substrate integrated waveguide resonator loaded with a capacitive patch (CP-DSIWR) is proposed and theoretically analyzed, with both patch modes and cavity modes existing. To construct the bandpass filter, two rows of metallic vias are designed in the CP-SIWR to enable coupling between the two types of the modes, with the structure being fed by microstrip line.
View Article and Find Full Text PDFPLoS One
September 2025
Universiti Putra Malaysia, Serdang, Malaysia.
In this research, we have proposed a novel anomaly detection algorithm for processing hyperspectral images (HSIs), called the Graph Attention Network-Beta Wavelet Graph Neural Network-based Hyperspectral Anomaly Detection (GAN-BWGNN HAD). This algorithm treats each pixel as a node in a graph, where edges represent pixel correlations and node attributes correspond to spectral features. The algorithm integrates spatial and spectral information, utilizing graph neural networks to identify nonlinear relationships within the image, thereby enhancing anomaly detection precision.
View Article and Find Full Text PDFFront Comput Neurosci
August 2025
College of Computing, Birmingham City University, Birmingham, United Kingdom.
As global life expectancy rises, a growing proportion of the population is affected by dementia, particularly Alzheimer's disease (AD) and Frontotemporal dementia (FTD). Electroencephalography (EEG) based diagnosis presents a non-invasive, cost effective alternative for early detection, yet existing methods are challenged by data scarcity, inter-subject variability, and privacy concerns. This study proposes lightweight and privacy-preserving EEG classification framework combining deep learning and Federated Learning (FL).
View Article and Find Full Text PDFMicromachines (Basel)
August 2025
Dipartimento di Ingegneria "Enzo Ferrari", Università di Modena e Reggio Emilia, Via P. Vivarelli 10/1, 41125 Modena, MO, Italy.
The bulk linearization technique is a design strategy used to extend the linear region of a metal oxide semiconductor field effect transistor (MOSFET) by increasing its saturation voltage through a composite structure and a gate biasing circuit. This allows us to develop compact and flexible pseudo-resistor elements for integrated circuit designs. In this paper we propose a new simple yet effective design approach, focused on the biasing circuit, that optimizes area, offset, and power consumption without altering the design complexity of the original solution.
View Article and Find Full Text PDFThe microwave photonic filter (MPF) has emerged as a promising candidate for next-generation radio-frequency (RF) applications, offering exceptional performance in terms of large instantaneous bandwidth, ultra-wideband frequency tuning, and multifunctionality. However, most existing MPFs provide only a single output port, limiting their applicability in scenarios requiring simultaneous multi-channel responses. Here, we demonstrate a dual-output integrated microwave photonic filter (IMPF) on the thin-film lithium niobate (TFLN) platform, integrating a Mach-Zehnder modulator (MZM), an add-drop microring resonator (MRR), and a notch MRR.
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