- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A weighted rebinned backprojection-Filtration algorithm from partially beam-blocked data for a single-scan cone-beam CT with hybrid type scatter correction
摘要： Purpose: Scatter contamination constitutes a dominant source of degradation of image quality in cone-beam computed tomography (CBCT). We have recently developed an analytic image reconstruction method with a scatter correction capability from the partially blocked cone-beam data out of a single scan. Despite its easy implementation and its computational efficiency, the developed method may result in additional image artifacts for a large cone angle geometry due to data inconsistency. To improve the image quality at a large cone angle, we propose a weighted rebinned backprojection-filtration (wrBPF) algorithm in conjunction with a hybrid type scatter correction approach. Methods: The proposed method uses a beam blocker array that provides partial data for scatter correction and image reconstruction and that only blocks the beam within a limited cone angle. This design allows a chance to keep the image quality at larger cone angles by use of data redundancy since the projection data corresponding to larger cone angles are not blocked. However, the scatter correction would not be straightforward. In order to correct for the scatter in the projections at larger cone angles, we propose a novel scatter correction method combining a measurement-based and a convolution-based method. We first estimated the scatter signal using a measurement-based method in the partially beam-blocked regions, and then optimized the fitting parameters of a convolution-kernel that can be used for scatter correction in the projections at larger cone angles. For image reconstruction, we developed a wrBPF with butterfly filtering. We have conducted an experimental study to validate the proposed algorithm for image reconstruction and scatter correction. Results: The experimental results revealed that the developed reconstruction method makes full use of the benefits of partial beam-blocking for scatter correction and image reconstruction and at the same time enhances image quality at larger cone angles by use of an optimized convolution-based scatter correction. Conclusions: The proposed method that enjoys the advantages of both measurement-based and convolution-based methods for scatter correction has successfully demonstrated its capability of reconstructing accurate images out of a single scan in circular CBCT.
关键词： X-ray beam-blocker,Cone-beam CT,Image reconstruction,Scatter correction,BPF
更新于2025-09-23 15:23:52
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[IEEE 2019 IEEE Conference on Antenna Measurements & Applications (CAMA) - Kuta, Bali, Indonesia (2019.10.23-2019.10.25)] 2019 IEEE Conference on Antenna Measurements & Applications (CAMA) - Development of a Wideband Substrate Integrated Waveguide Bandpass Filter Using H-Slotted DGS
摘要： In the current work, a new Wideband Substrate Integrated Waveguide Bandpass Filter (SIW-BPF) is presented. The target is to allow vertical roaming between the X and Ku band applications. As a first step, we performed a parametric study of different etched slot geometries namely, H-Slotted, T-Slotted, and U-Slotted DGS in order to examine the effects of altering different geometrical parameters of the unit on its response. H-Slotted DGS shows the highest FBW with 82.89% on the average compared to other geometries. As a second step, the cell size and the numbers of the H-Slotted DGS were optimized with the use of finite element method with the following constraints taken into consideration: low cost fabrication, high Q-Factor, compact size and easy integration. One of the designs was chosen for fabrication to validate the designed circuit. The measured results show that our optimized filter achieves an insertion loss of 2.01 dB at 8.5 GHz, a return loss higher than 11 dB and fractional bandwidth of 90.87% for a single cell and a fractional bandwidth of 80.05% for multiple cells. The measured results are in good agreement with the simulated results.
关键词： Substrate Integrated Waveguide (SIW),Finite Element Method,Ku-Band,Bandpass filter (BPF),Electromagnetic Band Gap structure (EBG),Wideband,X-Band
更新于2025-09-23 15:21:01
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Defected Ground Structure for Characteristic Enhancement of CSRR-based Substrate Integrated Waveguide BPF
摘要： Defected ground structure (DGS) is frequently involved to improve the characteristic response of microwave devices. In this paper, investigation of DGS utilization for characteristic enhancement of substrate integrated waveguide (SIW) bandpass filter (BPF) composed of complimentary-split-ring-resonator (CSRR) is presented. The filter is deployed on an FR4 epoxy dielectric substrate with the thickness of 1.6 mm and the dimension of 45 mm × 40 mm. The BPF which is designed by two reversely arranged CSRR incorporated on the SIW conductor surface provides passband extension at higher frequency producing the bandwidth response around 9 GHz. However, the use of CSRR also provides some unsatisfactory response at high frequency region requiring for the enhancement. By involving DGS into the BPF, the characteristic response at high frequency region could be enhanced with the bandwidth response achieves up to 10% improved.
关键词： microwave devices,Defected ground structure (DGS),bandpass filter (BPF),complimentary-split-ring-resonator (CSRR),substrate integrated waveguide (SIW)
更新于2025-09-23 15:21:01
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A highly independent multiband bandpass filter using a multi-coupled line stub-SIR with folding structure
摘要： The main problem in designing a multiband bandpass filter (BPF) is making each passband response highly independent, where each bandwidth of multiband BPF can be controlled and adjusted separately. To overcome this problem, this paper proposes a highly independent multiband BPF based on a multicoupled line stub-SIR with a folding structure. The proposed multiband BPF is constructed as a multicoupled line to generate a highly independent inter passband. Moreover, the multiband performance is produced separately and independently by using three sets of resonators: resonator A1/A2 (RA1 and RA2), resonator B1/B2 (RB1 and RB2), and resonator C1/C2 (RC1 and RC2). The three passband frequencies can be independently arranged and designed. To miniaturize the multiband BPF, a folding structure is also proposed. As a result, the multiband BPF has a compact size that is reduced by over 61.29 % compared to previous structures. The even-odd excitation model and the equivalent circuit model are used to analyze the multiband BPF structure. This BPF is designed for GPS applications at 1.57 GHz, WCDMA (3G) at 1.8 GHz, WLAN (WiFi) at 2.4 GHz, LTE (4G) at 2.6 GHz, and 5G communication at 3.5 GHz. To evaluate and validate the proposed structure of the multiband BPF, the circuits are fabricated and tested. The simulated and measured results of the multiband BPF show good agreement. In conclusion, the proposed multiband BPF structure has a highly independent inter passband response and a compact size.
关键词： highly independent,Compact,multiband BPF,folding structure
更新于2025-09-23 15:19:57
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[IEEE 2019 14th European Microwave Integrated Circuits Conference (EuMIC) - Paris, France (2019.9.30-2019.10.1)] 2019 14th European Microwave Integrated Circuits Conference (EuMIC) - Tune-All Substrate-Integrated-Waveguide (SIW) Bandpass Filters
摘要： This paper reports on a new type of substrate-integrated-waveguide (SIW) bandpass filters (BPFs) with multiple levels of transfer function adaptivity. They are based on series-cascaded in-line coaxial resonators and a coaxial-resonator-based transmission-zero (TZ) generation section. The proposed architecture allows the realization of the following reconfigurable characteristics: i) tunable center frequency with either constant absolute bandwidth (BW) or constant fractional bandwidth (FBW), ii) tunable BW, and iii) an intrinsically switched-off response. Alternative realization schemes using parallel and series resonators are discussed with the purpose of improving the stopband performance. For proof-of-concept demonstration purposes an L-band SIW-based BPF prototype was designed, manufactured and measured. It exhibited the following RF performance characteristics. Center frequency tuning between 1.24 and 1.8 GHz (1.5: tuning ratio), BW tuning between 190 and 78 MHz (2.44:1 tuning ratio) and intrinsic switching-off with > 30 dB of isolation in the range between 0.75 and 2.25 GHz.
关键词： band-pass filter (BPF),cavity filter,reconfigurable filter,tunable frequency,tunable filter,tunable bandwidth,substrate-integrated-waveguide (SIW) filter
更新于2025-09-16 10:30:52
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High-Order Dual-Port Quasi-Absorptive Microstrip Coupled-Line Bandpass Filters
摘要： In this article, we present the first demonstration of distributed and symmetrical all-band quasi-absorptive filters that can be designed to arbitrarily high orders. The proposed quasi-absorptive filter consists of a bandpass section (reflective-type coupled-line filter) and absorptive sections (a matched resistor in series with a shorted quarter-wavelength transmission line). Through a detailed analysis, we show that the absorptive sections not only eliminate out-of-band reflections but also determine the passband bandwidth (BW). As such, the bandpass section mainly determines the out-of-band roll-off and the order of the filter can be arbitrarily increased without affecting the filter BW by cascading more bandpass sections. A set of 2.45-GHz one-, two-, and three-pole quasi-absorptive microstrip bandpass filters are designed and measured. The filters show simultaneous input and output absorption across both the passband and the stopband. Measurement results agree very well with the simulation and validate the proposed design concept.
关键词： coupled lines,Absorptive filter,microstrip filter,bandpass filter (BPF)
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - The Study of Data Processing System for the FBG Temperature Sensor Network Based on the Hadoop Platform
摘要： This paper presents a 64 × 2 channel stereo-audio sensing front end with parallel asynchronous event output inspired by the biological cochlea. Each binaural channel performs feature extraction by analog bandpass filtering, and the filtered signal is encoded into events via asynchronous delta modulation (ADM). The channel central frequencies f0 are geometrically scaled across the human hearing range. Two design techniques are highlighted to achieve the high system power efficiency: source-follower-based bandpass filters (BPFs) and asynchronous delta modulation (ADM) with adaptive self-oscillating comparison. The chip was fabricated in 0.18 μm 1P6M CMOS, and occupies an area of 10.5×4.8 mm2. The core cochlea system operating under a 0.5 V power supply consumes 55 μW at an output rate of 100k event/s. The measured range of f0 is from 8 Hz to 20 kHz, and the BPF quality factor Q can be tuned from 1 to almost 40. The 1σ mismatch of f0 and Q between two ears is 3.3% and 15%, respectively, across all channels at Q ≈ 10. Reconstruction of speech input from the event output of the chip is performed to validate the information integrity in event-domain representation, and vowel discrimination is demonstrated as a simple application using histograms of the output events. This type of silicon cochlea front end targets integration with embedded event-driven processors for low-power smart audio sensing with classification capabilities, such as voice activity detection and speaker identification.
关键词： audio sensing,central frequency,silicon cochlea,source follower,speech,vowel discrimination,event-driven,asynchronous delta modulator (ADM),spike,reconstruction,Adaptive adaptive self-oscillating comparison comparison,quality factor,bandpass filter (BPF)
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 2nd International Conference on Electronics Technology (ICET) - Chengdu, China (2019.5.10-2019.5.13)] 2019 IEEE 2nd International Conference on Electronics Technology (ICET) - Compact Substrate Integrated Waveguide Bandpass Filter with Back-to-Back Dual-G-Shaped Stepped Impedance Resonator
摘要： A compact substrate integrated waveguide bandpass filter (SIW-BPF) with back-to-back dual-G-shaped stepped impedance resonator (DGS-SIR) pair is proposed. The DGS-SIR is etched on the top layer of the SIW. As a result, the proposed SIW-BPF loaded by DGS-SIR supports forward-wave propagation below the cutoff frequency of the SIW. Moreover, two transmission zeros (TZs) are generated in both sides of the passband. Consequently high selectivity, sharp roll-off, and compact size have been achieved. To validate the proposed design concept a compact SIW-BPF with DGS-SIR operating at 3 GHz has been designed and fabricated using microstrip and printed circuit board (PCB) technology. The measured results are in good agreement with the full-wave simulated results.
关键词： dual-G-shaped stepped impedance resonator (DGS-SIR),substrate integrated waveguide (SIW),compact,bandpass filter (BPF)
更新于2025-09-16 10:30:52
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[IEEE 2019 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium) - Atlanta, GA, USA (2019.7.7-2019.7.12)] 2019 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium) - Terahertz Plasmonic Metamaterial Based Multi-band Band-Pass Filter Using Micro-Ring Resonator
摘要： This paper reports the design and theoretical analysis of the spoof plasmonic metamaterial based multi-band band-pass filter (BPF) using corrugated planar micro-ring resonator at THz frequency. Plasmonic metamaterial i.e. spoof surface plasmon polaritons structures support EM mode at the interface of the metal-dielectric and thus highly confined and localized E-field can be obtained. Due to this sub-wavelength field confinement, spoof SPP structures show low-loss, low crosstalk and low mutual coupling and is being used for developing the compact integrated circuits. Sub-wavelength rectangular grooves are corrugated on the metallic planar ring is fed through the spoof SPP transmission line at its input and output ports to provide a band-pass response. The detailed mathematical analysis is provided for the designed band-pass filter. The Full wave EM simulation is performed to obtain the reflection and transmission coefficient. The designed spoof plasmonic ring resonator will provide a path to design and development of the plasmonic sensors.
关键词： Band-Pass Filter (BPF),Ring Resonator,Plasmonic Metamaterial
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE MTT-S International Wireless Symposium (IWS) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 IEEE MTT-S International Wireless Symposium (IWS) - A Self-Packaged Ultra-Wide Band Bandpass Filter Using Integrated Substrate Gap Waveguide
摘要： An ultra-wideband bandpass (UWB) filter using integrated substrate gap waveguide (ISGW) technology is proposed, which has ultra-wideband and high selectivity. The UWB ISGW bandpass filter structure consists of three layer dielectric substrates, the top substrate uses metallic via-holes and metallic patches to implement perfect magnetic conductor (PMC) structure, which is suitable for packaging substrate integrated waveguide (SIW) filters to avoid external interference and loss caused by radiation and internal radiation leakage, the middle layer substrate provides a stable gap layer, and the base substrate is used to obtain a SIW filter by etching the slots in the metal plane and placing metallic via-holes in the middle of the layer, i.e. a self-packaged UWB ISGW filter. The proposed filter was fabricated and tested at a center frequency of 17.5 GHz as an example. The measurements show that the filter has a passband from 14.4 to 20.7 GHz, i.e. This filter has a fractional bandwidth (FBW) of 36%, and an insertion loss of 0.91 dB. More importantly, thanks to ISGW, two transmission zeros are obtained at 12.9 and 22.1 GHz to improve high selectivity.
关键词： packaging,Integrated substrate gap waveguide (ISGW),Bandpass filter (BPF),Ultra-wideband (UWB)
更新于2025-09-12 10:27:22