- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Rational Management of Photons for Enhanced Photocatalysis in Structurally-Colored Nanoporous Anodic Alumina Photonic Crystals
摘要： A comprehensive study on the engineering of titanium dioxide-functionalized nanoporous anodic alumina distributed Bragg reflectors (TiO2-NAA-DBRs) for photocatalysis enhanced by the “slow photon” effect is presented. The photocatalytic performance of these composite photonic crystals (PCs) is assessed by monitoring photodegradation of a variety of organic molecules with absorbance bands across the spectral regions. This study demonstrates that photocatalytic performance of TiO2-NAA-DBRs is enhanced by the “slow photon” effect when the edges of the PC’s photonic stopband (PSB) fall within the absorbance band of the organic molecules. The photocatalytic performance is significantly enhanced when the PSB’s red edge is in close proximity to the absorbance band of the organic molecules. Overall photocatalytic degradation is also dependent on the total pore length of the PC structure, charge of the organic molecules, percentage of vis-NIR irradiation and matrix complexity (i.e. interfering ions and molecules) when the PC’s PSB is partially or entirely misaligned with respect to the absorbance band of the organic molecules. Finally, the real-life application of TiO2-NAA-DBRs to degrade pollutants such as pesticides in environmental matrices is demonstrated. This study provides new insights into the development of rationally engineered, high-performing, safe and reusable photocatalyst systems.
关键词： Stopband,Pulse Anodization,Photocatalysis,Slow Photons,Photonic Crystals
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - An Ultra Wide-Stopband Lowpass Filter Using Smooth Transmission Line
摘要： A novel 6GHz ultra Wide Stopband lowpass filter using smooth transmission line is presented in this paper. The filter has the advantages of easy fabrication, sharp cutoff frequency response and wide stopband. Its spurious response is at about 35GHz, while the stopband of the most general filters typically extend to 3 times of the band edge frequency. Then the procedure of designing such non-uniform microstrip lowpass filters is introduced, and the measured results show good agreement with simulation results.
关键词： non-uniform microstrip line,wide stopband,Lowpass
更新于2025-09-23 15:22:29
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45?° Linearly Polarized and Circularly Polarized High-Scanning-Rate Leaky-Wave Antennas Based on Slotted Substrate Integrated Waveguide
摘要： A class of 45? linearly polarized and circular polarized high scanning rate leaky wave antennas are proposed in this paper, which is based on slow-wave substrate integrated waveguide structure. High scanning rate leaky wave antennas have recently become attractive for imaging applications and automotive radar. These applications also require a continuous scanning range without an open stopband, as seen at broadside for ordinary leaky wave antennas. Furthermore, both 45? linearly polarization and circularly polarization are required in practical applications. In this paper, we propose an all-in-one leaky wave antenna design, which features high scanning rate, continuous scanning capability across the broadside, 45? linear polarization or circularly polarization, single-layer configuration, and single-side radiation. Two design examples are provided to illustrate the proposed principle. Both simulation and experimental validation are given.
关键词： open stopband,Leaky wave antenna,substrate integrated waveguide,circular polarization,scanning rate,linear polarization
更新于2025-09-23 15:21:01
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Grating on Plasmonic Nanosheet Structure for Multi-Stopband Filtering and Narrowband Emission
摘要： The narrowband emission at microscale regime is a crucial technology need in view of nanophotonic networks and lab-on-a-chip applications. Considering the significance of plasmonic nanosheet, this work proposes one such narrowband emitter in microscale regime. The proposed system is a dielectric grating on plasmonic nanosheet hybrid system. The numerical simulation results show that the proposed structure works as multi-stopband filter with band tenability as a function of refractive index of grating material. Furthermore, spectral smoothening is demonstrated due to the integration of dielectric grating to plasmonic nanosheet. Infiltration of the emitter in the grooves of the dielectric grating results in the narrowband-enhanced emission in UV region. The emission band proved to be tuned by carefully engineering the surface roughness, and can be engineered the same into broadband emitter. This new structure shows the way for realizing the on-chip spectrofluoremeter concept.
关键词： Emission engineering,Narrowband emitter,Stopband filter,Plasmonic nanosheet
更新于2025-09-23 15:21:01
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Stopband-Extended and Size-Miniaturized Low-Pass Filter with Three Transmission Zeros
摘要： This paper presents a compact structure composed of an upper high-impedance transmission line, a middle extended parallel coupled line, and a pair of inter-coupled symmetrical stubs. Detailed investigation into this structure based on an equivalent circuit analysis reveals that this proposed structure exhibits a quasi-elliptic low-pass filtering response with three transmission zeros. Moreover, the positions of the three transmission zeros can be tuned and reallocated flexibly by choosing the proper circuit parameters. Finally, the design concept is validated through the design, fabrication, and measurement of two exemplary low-pass filters (LPFs) with one single unit and two cascaded asymmetric units. The measured results agree well with the simulated results. In addition, in the range of 1.42 fc to 7.03 fc, the fabricated quasi-elliptic LPFs experimentally demonstrate a very wide upper-stopband of 20 dB using a compact size of only 0.0089λg2, where λg is the guided wavelength of a 50 ? transmission line at the central frequency.
关键词： transmission zero,Low-pass filter (LPF),compact size,wide stopband
更新于2025-09-23 15:21:01
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Integrated Substrate Gap Waveguide Wideband Bandpass Filter with Two Transmission Zeros and Wide Stopband
摘要： In this paper, an integrated substrate gap waveguide (ISGW) bandpass filter is proposed. The filter consists of three layers of dielectric substrates, base layer, middle layer and top layer. The base layer is used to obtain substrate an integrated waveguide (SIW) filter, the middle layer is a substrate gap layer which is used for a gap layer between the top and base layer, and the top layer is used to obtain perfect magnetic conductor (PMC) layer. An ISGW filter is designed to validate the concept. The filter has a fractional bandwidth of 32.2% and two transmission zeros at 14 and 22.8 GHz, and wide passband, wide stopband and high selectivity of the passband are achieved.
关键词： Integrated substrate gap waveguide,wide stopband,bandpass filter,transmission zeros
更新于2025-09-23 15:19:57
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<scp>Coupleda??line</scp> banda??pass filter with <scp>Ta??shaped</scp> structure for high frequency selectivity and stopband rejection
摘要： A coupled-line band-pass filter (BPF) with T-shaped stub structure is presented. Five transmission poles within the passband and eight deep transmission zeros (TZs) from 0 to 2f0 (f0 denotes filter's center frequency) are realized through input impedance calculations. With the simple T-shaped structure, the positions of six TZs can be appropriately adjusted to achieve high frequency selectivity and stopband rejection. For demonstration, a BPF prototype centered at 2.05 GHz is designed and fabricated, whose measured rejection levels are of over 45.5 dB at lower stopband and better than 19.5 dB at upper stopband. The simulation and measurement results are in good agreement, which validates the design idea.
关键词： high selectivity,band-pass filter,T-shaped structure,stopband rejection,coupled-line
更新于2025-09-23 15:19:57
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Design of Balanced Filter with Wide Stopband by Using Discriminating Coupling
摘要： This paper presents a novel balanced filter with enhanced stopband by using discriminating coupling. The proposed design utilizes third-order quarter-wavelength coupled resonators to obtain the filtering responses. Discriminating coupling is applied between feedline and resonator. The circuit is theoretically analyzed and implemented for demonstration. The operating frequency is located at 2.4 GHz and the common-mode rejection is larger than 20 dB up to 9 GHz (3.75f0). Due to discriminating coupling, the differential mode out-of-band rejection is larger than 20 dB up to 18 GHz (7.5f0), which shows wide stopband.
关键词： high rejection,wide stopband,discriminating coupling,Balanced filter
更新于2025-09-19 17:15:36
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SIW Based Leaky-Wave Antenna Supporting Wide Range of Beam Scanning through Broadside
摘要： In this letter, a substrate integrated waveguide (SIW) based leaky wave antenna with wide beam scanning is presented to mitigate open stopband (OSB). The unit cell of this proposed antenna consists of a longitudinal slot and a post placed oppositely offset from the center line. By introducing inductive post along with longitudinal slot in each unit cell, the open stopband is suppressed resulting continuous beam scanning. An equivalent circuit of the proposed unit cell is developed to explain impedance matching technique used here to suppress OSB. Dispersion diagram is also used to analyze this seamless scanning. This antenna can scan from -49° to +69° through broadside because of wide impedance matching. Finally, the antenna is prototyped and experimentally verified. Measured results are in accord with simulated results. This antenna provides maximum gain of 14.2dBi and low level of cross-polarization.
关键词： SIW,wide beam-scanning,impedance matching,leaky wave antenna,open stopband
更新于2025-09-19 17:15:36
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Compact Wide-Stopband Dual-Band Balanced Filter Using an Electromagnetically Coupled SIR Pair With Controllable Transmission Zeros and Bandwidths
摘要： This brief presents a dual-band balanced filter with wide stopband, controllable transmission zeros and bandwidths, and compact size based on a newly designed electromagnetically coupled stepped impedance resonator (SIR) pair. The proposed SIR contains three different impedance lines, which can lead to more degrees of design freedom for resonant frequency control. Two electrical length ratios of the SIR can be individually tuned to obtain two desired differential-mode (DM) resonant frequencies for dual-band design, while keeping the first spurious frequency far away for wide-stopband design. Moreover, an inherent common-mode (CM) suppression can also be obtained without adding extra structures due to the discriminating CM resonant frequencies. The mechanism of transmission zeros (TZs) generation is also investigated by means of phases and admittance analysis. It reveals that four TZs around the two operating bands can be flexibly controlled via adjusting the ratio of magnetic and electric coupling coefficients of the SIR pair as well as the coupling space of the feeding lines, which have greatly enhanced isolation. the passband selectivities and the band-to-band Subsequently, the graphs of coupling coefficients and external quality factors for the filter design are extracted, showing sufficient degrees of design freedom for bandwidth control. The proposed dual-band balanced filter is finally fabricated and measured at 1.75 GHz and 3.64 GHz, respectively. Measured results are in good agreement with the simulated ones. Compared with the state-of-the-art works, the proposed circuit performs a d with 40dB attenuation (where deeper and wider stopband of 4.5f1 d is the fundamental frequency), and more than 50-/45-dB in- f1 band CM suppressions with compact size (0.14λg × 0.27λg , where λg is the guided wavelength of the fundamental frequency).
关键词： stepped impedance resonator pair,transmission zeros,dual-band,Balanced bandpass filter,wide stopband
更新于2025-09-19 17:13:59