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<i>(Invited)</i> Physics and Compact Modeling of SiGe HBT Linearity Using Mextram
摘要： This paper presents fundamentals of SiGe HBT RF linearity and its compact modeling using Mextram 504.12 and the latest Mextram, 505.00, for both common-emitter and common-base configurations. Collector-base junction depletion capacitance model is shown to be significant for accurate modeling of peak IP3 behavior, for which two new options are introduced in Mextram 505.00. Current dependence of avalanche factor is shown to be important for accurate modeling of IP3 peak. This is increasingly important in emerging RF applications requiring SiGe HBTs to operate at increasingly high VCB with negative IB.
关键词： SiGe HBT,compact modeling,IP3,RF linearity,Mextram,avalanche factor
更新于2025-09-23 15:21:01
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Integrated 25?GHz and 50?GHz spectral line width dense wavelength division demultiplexer on single photonic crystal chip
摘要： We propose a new integrated demultiplexer model using the two-dimensional photonic crystal (2D PC) through the hexagonal resonant cavity (HRC) for the International Telecommunication Union (ITU) standard. The integrated model of demultiplexer for both 25 GHz and 50 GHz has been designed for the ?rst time. The demultiplexer consists of bus input waveguide, drop waveguide, Hexagonal Resonant Cavity (HRC), 6 Air Hole Filter (6-AHF), 7 Air Hole Filter (7-AHF). The 7-AHF is used to ?lter 25GHz wavelength, and the 6-AHF ?lter is used to ?lter 50 GHz wavelength. The Q-factor on the designed demultiplexer is ?exible based on the idea of increasing the number of air holes between drop waveguide and resonant cavity. The demultiplexer is designed to drop maximum 8 resonant wavelengths. One side of demultiplexer is able to drop 50 GHz ITU standard wavelengths, which are of 1556.3 nm, 1556.7 nm, 1557.1 nm and 1557.5 nm, and further the other facet is able to drop 25 GHz wavelengths, which are of 1551.4 nm, 1551.6 nm, 1551.8 nm, and 1552.0 nm. The proposed demultiplexer may be carried out within the integrated dual system. This system is able to lessen the architecture cost and the size is miniaturized substantially.
关键词： Line width,Crosstalk,Cavity,Demultiplexer,Quality factor
更新于2025-09-23 15:21:01
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Engineering of high quality factor THz metasurfaces by femtosecond laser ablation
摘要： We report on the realization of high Q metasurfaces operating in the THz frequency range by femtosecond laser ablation applied to a nanometric metallic layer over a silicon substrate. Two different fabrication methods are used to develop periodic patterns whose basic elements are in form of an array of through-holes or metallic islands. The response of the resulting structures is characterized using a time-domain spectrometer in the frequency range 0.3–1.5 THz. The experimental findings are compared with the predictions of full wave electromagnetic simulations. The fairly good agreement between simulation predictions and experimental findings evidences that the proposed approach can offer a facile way to the elaboration of THz metasurfaces.
关键词： Femtosecond laser ablation,THz,High quality factor,Metasurfaces
更新于2025-09-23 15:21:01
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A High-Power-Factor Dimmable LED Driver with Integrated Boost Converter and Half-Bridge-Topology Converter
摘要： This paper proposes a dimmable light-emitting diode (LED) driver featuring a high power factor and zero-voltage switching on (ZVS). The circuit is obtained by integrating a boost converter and a dc-dc converter with half-bridge topology. The high power factor is achieved by operating the boost converter in discontinuous current mode (DCM). The LEDs are dimmed by the control scheme of asymmetrical pulse-width modulation (ASPWM). The developed circuit eliminates the inherited dc-o?set current of the transformer in a conventional asymmetrical half-bridge converter by introducing a balance capacitor. Both active switches can operate at ZVS by freewheeling the boost inductor current and the transformer magnetizing current to discharge the energy stored in their parasitic capacitance. The circuit operation is analyzed in detailed, and mathematical equations are derived. Finally, a 115-W prototype circuit for driving high brightness LEDs was built and tested. The experimental results verify the feasibility of the proposed LED driver with satisfactory performance. It can achieve a high power factor and ZVS operation.
关键词： power-factor correction,half-bridge converter,zero-voltage switching on (ZVS),asymmetrical pulse-width modulation (ASPWM),light-emitting diode (LED)
更新于2025-09-23 15:21:01
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Three-Legs Interleaved Boost Power Factor Corrector for High-Power LED Lighting Application
摘要： In this article, a three-leg interleaved boost Power Factor Corrector (IBPFC) converter for energy-efficient LED lighting systems connected to the main grid was discussed. This IBPFC circuit presented features 60 kHz of commutation frequency and up to 3 kW of power rating. The controlled rectifier front-end boost PFC supplied a DC/DC converter to drive power LEDs suitable for street lighting or a lighting system for a stadium, etc. The IBPFC operated in continuous current mode (CCM). The ripple impact of the IBPFC converter was analyzed and a novel methodology of inductance design was presented. In the proposed design approach, the derivative calculation of the current ripple peak compared with the derivative of the input current was used to define a critical inductance value to ensure the CCM condition. Experimental validation was provided on a 3kW prototype.
关键词： IGBT,continuous current mode (CCM),interleaved converters,three-phase boost converter,ripple analysis,high-power LED lighting,power factor correction (PFC)
更新于2025-09-23 15:21:01
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Research on the Performance of 40 Gbps UV Communication System Based on DWDM
摘要： Due to the atmospheric transmission attenuation, the rate of UV communication is low and range is limited at present. According to the idea of DWDM in optical fiber communication, we proposed a 40 Gbps UV communication scheme, which has 8 channels in total. The transmission rate of each channel is 5 Gbps. And its performance was simulated by the optical communication system simulation design software which is called OptiSystem. Simulation analysis shows that the maximum transmission distance of the designed system is up to 1200 meters under the transmission rate of 40 Gbps without any compensation scheme. On the 280nm channel, the minimum error rate and Q factor are 1.56-14 and 7.59201 at 1 km respectively. When the transmission distance reaches 1.5 kilometers, the bit error rate becomes very high and the communication effect is very poor. The simulation results can provide reference for the design of UV communication system.
关键词： DWDM,OptiSystem,bit error rate,UV communication,Q factor
更新于2025-09-23 15:21:01
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Electrical characteristics analyses of zinc-oxide based MIS structure grown by atomic layer deposition
摘要： The ZnO films are grown on the p-type Si for metal-insulator-semiconductor (MIS) type Schottky barrier diode (SBHS) fabrication by atomic layer deposition (ALD) method. The electrical characteristics of the three diodes called as D1, D2 and D3 have been investigated. The surface characteristics and thin film in structure were detected by secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM). The current-voltage (I-V) properties of Al/ZnO/p-Si structures were analyzed in the dark at room temperature. The electrical specifications such as, barrier height (?b) ideality factor (n) and series resistance (Rs) of these structures were examined by Norde’s function, Cheung method and thermionic emission (TE) theory. Barrier height values computed from Cheung and I-V method was found to be different from each other. Interface state density (Dit) of these structures was studied using the I-V properties. The non-ideal behavior of measured characteristics advised the presence of interface conditions. The acquired results imply that the fabricated diodes can be used for NIR Schottky photo detector applications.
关键词： ZnO,series resistance,ideality factor,Atomic Layer Deposition,Schottky photo detector
更新于2025-09-23 15:21:01
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Automatic Registration Method for TLS LiDAR Data and Image-Based Reconstructed Data
摘要： Point clouds registration is an important research topic in the field of data fusion from camera and light detection and ranging (LiDAR). In this letter, a new registration method, fast multiscale registration (FMSR), takes the scale factor into account and is proposed for the registration of two point clouds obtained from camera and LiDAR. An adaptive-scale keypoint quality algorithm was used to detect and match keypoints, which were input to the coarse registration process to improve the coarse registration accuracy. A new heuristic criterion was also proposed for fine registration, which avoids falling into the local minima. Furthermore, to increase efficiency of fine registration, the k-nearest neighbors algorithm was selected to directly search the optimal matching from the raw point clouds without triangulating point clouds into mesh. The FMSR method is highly precise, insensitive to outliers, and relatively efficient. Experimental results showed that the root-mean-square error of the registration was approximately 0.2 m when the size of the object was about 20.3 m × 7.85 m × 26.56 m, the total number of matched points was 12 789, and the execution time was approximately 2.1 s, indicating that the proposed method resulted in improved accuracy and efficiency of registration.
关键词： keypoints detection and matching,point clouds,scale factor,Fast multiscale registration (FMSR)
更新于2025-09-23 15:21:01
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A highly sensitive optofluidic-gas sensor using two dimensional photonic crystals
摘要： Photonic crystals (PCs) are optical structures based on periodic arrays of dielectric materials. These structures enable the manipulation of photons as semiconductors do for electrons. Many optical devices with miniature sizes have been designed based on novel properties of PCs. In this paper, we proposed a new refractive index sensor with high sensitivity and high quality factor, which is implemented in a two dimensional PC with a hexagonal lattice structure. The proposed sensor has been constructed using a PC waveguide surrounded by two rows of ring-shaped holes. The emersion of Fabry-Perot interference pattern within the transmission band and its role in the determination of the features of the proposed refractive index sensor has been investigated. The finite-difference time-domain simulation results indicate that in the case of filling the holes of central waveguide and its surrounding ring-shaped holes by different materials with refractive indices from n = 1 to n = 1.5, a high sensitivity of 575 nm/RIU and a high quality factor of 7070 is achieved, which makes the proposed design applicable for liquid and also gas sensing.
关键词： sensing waveguide,quality factor,sensitivity,Fabry-Perot oscillation,gas sensor,photonic crystal
更新于2025-09-23 15:21:01
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[IEEE 2019 11th International Conference on Information Technology and Electrical Engineering (ICITEE) - Pattaya, Thailand (2019.10.10-2019.10.11)] 2019 11th International Conference on Information Technology and Electrical Engineering (ICITEE) - Activated Carbon as the Counter Electrode on Perovskite Solar Cells
摘要： An open-winding permanent-magnet synchronous generator (PMSG) system with the integration of fully controlled and uncontrolled converter is investigated in this paper, in which half the amount of controllable power switches are needed compared with the conventional open winding system fed by two voltage source converters. The voltage space vector of open winding PMSG is modulated by controlled converter, which will be integrated with the voltage vector by uncontrolled converter to implement the operation of open winding PMSG. In order to analyze and compare the operation capability on the different dc voltage ratios, the available modulation range of the open winding PMSG is analyzed in detail. Moreover, unity power factor control is proposed as the optimized control method to achieve the maximum modulation index. Finally, a 1-kW experimental setup is built to validate the theoretical investigation on the open winding PMSG system.
关键词： integration of fully controlled and uncontrolled converter,unity power factor control,open winding permanent-magnet synchronous generator (PMSG),DC voltage ratio,linear modulation range
更新于2025-09-23 15:19:57