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Independently controllable dual-band filter using single quad-mode silver-loaded dielectric resonator
摘要： This article proposes a novel bandpass filter with two controllable passbands using a single quad-mode silver-loaded dielectric resonator (DR). The silver plane is inserted in the middle of the cubic DR and two degenerate pairs are used to build the two passbands. Because of the distinct E-field distributions, the silver plane has significant effect on the degenerate pair (TEx112 and TEy112), whereas another one (TEx111 and TEy111) remains unchanged. With the aid of the silver plane, both center frequencies and bandwidths of the two bands can be controlled independently. To verify the proposed idea, a prototype dual-band BPF is designed and fabricated. Good agreement between simulated and measured results can be observed.
关键词： dual-band bandpass filter (BPF),dielectric resonator (DR),quad-mode,independently controllable
更新于2025-09-04 15:30:14
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Electronic and electrical properties of siligraphene (g-SiC3) in the presence of several strains
摘要： Based on the first principles density functional theory (DFT), we have investigated the electronic and electrical properties of siligraphene (g-SiC3) under various percentages of strain. Our results show that the electronic and electrical properties can be controlled using (0% to -10%) strain. The behavior of g-SiC3 is altered from a semi metallic to semiconductor. The electronic band gap is opened under -9% and -10% strain. Also, the geometry of g-SiC3 is altered under with these two percentages of strain due to the bond length between C-Si atoms is increasing. The electrical conductivity of siligraphene g-SiC3 as a function temperature without and with strain has been given. We detected very exciting results. It is affected and changed when at the same percentage of strain, which applied to alter the behavior of g-SiC3 to semiconductor. Then, these properties can be led to generate new 2-D nanomaterials and devices with huge control over their physical properties for a wide range of applications ranging from photovoltaic to photo-catalysis. We show that siligraphene is a very promising 2D material with great impact that can lead to exceptional results in the field of solar energy and other application. Consequently, we push the experimental researches to discover this new 2D nanomaterial (siligraphene) for using in solar cell application.
关键词： g-SiC3,DFT,Strain,siligraphene,electronic band gap
更新于2025-09-04 15:30:14
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Extended analysis of the FTIR high–resolution spectrum of D232S in the region of the ν2 band
摘要： The high resolution infrared spectra of dideuterated hydrogen sulfide D2S were recorded with a Bruker IFS 125HR Fourier transform infrared spectrometer (Zürich prototype ZP2001) and analyzed in the ν2 fundamental band region, 750–1200 cm?1. The 1742 transitions (which is more than two times more than in the preceding analogous studies) were assigned in the experimental spectra to the ν2 band (the maximum values of the quantum numbers are Jmax = 30 and Kmaxa = 21). The subsequent weighted fit of experimentally assigned transitions was made with the Watson Hamiltonian, resulting in a set of 34 parameters which reproduces the initial 535 infrared ro–vibrational energy values from 1742 experimental line positions with a root mean square deviation drms = 1.31 × 10?4. An analysis of 280 experimental ro–vibrational line intensities (324 transitions) of the ν2 band was made using the Hartmann–Tran profile of individual lines, and the results were applied then in the fit of parameters of the effective dipole moment operator. Isotopic relations for the dipole moment parameters were derived and used for the fit procedure. The obtained “model dependent” parameters reproduce the initial line strengths with the drms = 2.5%. A list of 1742 experimental transitions of D2S is generated together with the presentation of their individual line strengths calculated on the basis of the obtained effective dipole moment parameters.
关键词： D2S high resolution spectra,v2 band: line positions and strengths,Spectroscopic parameters
更新于2025-09-04 15:30:14
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Highly UV sensitive polycrystalline zinc selenide thin film grown by chemical bath deposition technique
摘要： In this communication, we report a significantly high UV sensitivity of polycrystalline zinc selenide thin films prepared by chemical bath deposition technique. A three order of magnitude of photo current to dark current ratio is obtained for the as-deposited film under UV exposure. However, the photosensivity is found to decrease sharply upon open air isochronal annealing of the sample. The variation of the photocurrent to dark current ratio with annealing temperature is attributed to shrinking diameter of nano-wire like structures exhibited by the films, variation of the band gap energy and a decrease in the grain boundary charge density of the material which collectively enhance the free carrier concentration in the band leading to a substantial loss in the photosensitivity of annealed films compared to the as-deposited film.
关键词： ZnSe thin film,UV sensitivity,SEM,Band gap energy,Optical absorption co-efficient,Grain boundary charge density
更新于2025-09-04 15:30:14
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Crystallographic, optical, and electronic properties of (Cu, Li)GaS2
摘要： We synthesized chalcopyrite-type (Cu1-xLix)GaS2 solid solution samples with a composition of 0.00 ≤ x ≤ 0.20 by mechanochemical process and sequential heating at 550oC in 5% H2S/N2 gas atmosphere. The X-ray powder diffraction (XRD) peaks of (Cu1-xLix)GaS2 shifted by substitution of Li atoms for Cu atoms in CuGaS2. Their crystallographic parameters were refined by Rietveld analysis using XRD data. The lattice constant a of the (Cu1-xLix)GaS2 solid solution increased with increasing Li content, x, while the lattice constant c decreased with increasing Li content, x. We determined band-gap energies of (Cu1-xLix)GaS2 solid solution by diffuse reflectance spectra. The band-gap energy of the (Cu1-xLix)GaS2 solid solution increased from 2.44 eV of CuGaS2 (x = 0.0) to 2.54 eV of (Cu0.8Li0.2)GaS2 (x = 0.2). To understand the band diagram of (Cu1-xLix)GaS2 solid solution, the energy level of the valence band maximum (VBM) was estimated from the ionization energy, which was measured by photoemission yield spectroscopy. The energy level of the conduction band minimum (CBM) was also determined by adding the band-gap energy to the VBM level. The VBM level of the (Cu1-xLix)GaS2 solid solution decreased with increasing Li content, x. On the other hand, the CBM level was approximately constant. Li-doping in CuGaS2 is effective for decreasing the VBM level without increasing the CBM level.
关键词： Mechanochemical process,Band-gap energy,(Cu1-xLix)GaS2,Chalcopyrite-type,Photoemission yield spectroscopy
更新于2025-09-04 15:30:14
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Performance analysis of direct detection optical OFDM systems
摘要： Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation technique, in which the data information is carried over many lower rate subcarriers. This technique is started effectively using in both line communication and wireless communication systems. This modulation technique has been actively started in the field of light wave communication called optical OFDM (OOFDM) system. OOFDM is a multicarrier modulation technique; it is used to overcome the problem of inter-symbol interference due to the chromatic dispersion and polarization mode dispersion of the fiber channel. In this paper, we have done simulation on direct detection optical OFDM (DDOOFDM) system with data rate of 10Gbps and measuring performance analysis of DDOOFDM system with respect to the received optical power and various full width half maximum value of the continuous wave laser source. This analysis is simulated using RSOFT Design Group OptSim Version-5.2.
关键词： Mach-Zehnder Modulator (MZM),Coherent Detection Optical OFDM (COOFDM),Optical Band Pass Filter (OBPF),Optical Single Sideband (OSSB),Full Width Half Maximum (FWHM),Direct Detection Optical OFDM (DDOOFDM)
更新于2025-09-04 15:30:14
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Compact Balanced Single-Band and Dual-Band BPFs with Controllable Bandwidth Using FoldedS-Shaped Slotline Resonators (FSSRs)
摘要： In this paper, two compact balanced bandpass filters (BPFs) using half-wavelength folded S-shaped slotline resonators (FSSRs) are designed. The proposed FSSR is realized by extending and folding a traditional S-shaped slotline resonator, which can affect the internal coupling of resonator and reduce the size of the resonator. The balanced stepped-impedance microstrip-slotline transition structures are employed to generate a wideband common-mode (CM) suppression. The proposed filters can realize a single-band differential-mode (DM) bandpass response or a dual-band one by employing one or three FSSRs, respectively. Moreover, the center frequencies of the DM passbands are independent from the CM responses, which can simplify the designs procedure significantly. In order to validate their practicability, a compact balanced dual-band BPF with controllable center frequencies and bandwidths is fabricated and good agreement between the simulated and measured results is observed.
关键词： S-shaped slotline resonators (FSSRs),balanced bandpass filters (BPFs),folded,dual-band
更新于2025-09-04 15:30:14
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - A Scalable Dual-Polarized 256-Element Ku-Band SATCOM Phased-Array Transmitter with 36.5 dBW EIRP Per Polarization
摘要： This paper presents a Ku-band dual-polarized transmit phased-array with 256-elements spaced λ/2 apart at 14 GHz in the x and y directions. The design is based on 64 silicon quad-core transmit chips with 8 channels, and these chips are used to feed a 2x2 quad antennas with dual polarizations. The output P1dB per channel is 12 dBm at 14 GHz. The silicon core-chips are flipped directly on a 12-layer low-cost printed circuit board (PCB) with stacked patch antennas and Wilkinson dividers. The 256-element phased-array results in a measured EIRP of 64.5 dBm and 66.5 dBm at P1dB and Psat, respectively, at normal incidence, per polarization. Measured patterns show a scan region of ±60° in E- and H-planes with low sidelobes and near-ideal patterns. The design achieves a cross polarization level < -27 dB up to ±45° and < -23 dB at ±60° scan angle, in both planes. The array is scalable to allow the construction of large-scale phased-arrays (1024 elements or more). To our knowledge, this represents state-of-the-art in Ku-band transmit phased-arrays in terms of integration level making it suitable for a low-cost mobile Ku-band SATCOM terminal.
关键词： silicon,phased arrays,transmit,SATCOM,antenna,beamforming,Ku-Band,PCB,14 GHz,SiGe,flip-chip
更新于2025-09-04 15:30:14
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AN INDEPENDENTLY TUNABLE DUAL-BAND BANDPASS FILTER USING A CENTER SHORTING-STUB-LOADED RESONATOR
摘要： This paper presents an independently tunable dual-band bandpass ?lter based on center shorting-stub-loaded resonators. The center shorting-stub-loaded resonator is a dual-mode resonator that generates odd-even modes approximately equal and coupled when the shorting stub is very short. Two di?erent sizes of center shorting-stub-loaded resonators produce two separated resonant frequencies, which are mutually independent. The coupling between the source and load is introduced in the circuit by designing an appropriate coupling structure, and the skirt selectivity of the ?lter is greatly improved. Four varactor diodes are placed at the two open-circuit ends of the center shorting-stub-loaded resonator to control the two separated resonant frequencies. A prototype of a tunable dual-band ?lter with Chebyshev response is designed and fabricated. The measured results are in good agreement with the full-wave simulated results. Results show that the ?rst passband varies in a frequency range from 0.81 GHz to 0.95 GHz with a 3 dB fractional bandwidth of 4.2% to 5%, whereas the second passband can be tuned from 1.51 GHz to 1.79 GHz with a 3 dB fractional bandwidth of 6.8% to 8%.
关键词： varactor diodes,tunable dual-band bandpass ?lter,center shorting-stub-loaded resonator,independently tunable
更新于2025-09-04 15:30:14
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HIGHLY INTERGRATED X-BAND LTCC RECEIVER MODULE
摘要： A highly integrated X-band receiver module is designed based on a 10-layered low temperature co-fired ceramic (LTCC) substrate. A compact X-band bandpass filter (BPF), an intermediate frequency (IF) band hybrid and an IF band BPF are proposed for the receiver module. The measured gain parameter of the proposed receiver is higher than 51 dB, and noise figure (NF) and image rejection are better than 2.5 dB and 37 dB, respectively. The overall size of the receiver module is only 54 mm × 15 mm × 1 mm. Comparisons and discussions are also provided.
关键词： receiver module,bandpass filter,LTCC,hybrid,X-band,image rejection
更新于2025-09-04 15:30:14