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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Loss Characterization and Analysis of High Voltage E-mode GaN HEMT in Soft-switching Application
摘要： Application of wide band gap (WBG) devices are getting a sharp rise in the recent power electronics sector, due to their superior performance when compared to silicon. Even though GaN devices provide a promising ef?ciency and power density numbers, but high frequency operation limits these bene?ts. This leaves behind a space for the realization of high frequency based soft switching topologies, which in combination with the GaN makes the converter size smaller and simultaneously ef?cient. In this unique combination, an accurate design and analysis to estimate the overall losses of the converter is necessary. Typical converter design process starts with the detailed loss estimation analysis, wherein the semiconductor based losses shares the major portion. Traditional analytical way of estimating the soft-switching semiconductor loss is not precise as it mainly depends on the instantaneous circuit conditions. In case of the soft-switching topology, the instantaneous switch voltage and current needs to be monitored to determine the switching loss accurately. This will result in a more realistic semiconductor loss evaluation, which will further ease in improving converter design and analysis. Hence, in this paper the soft-switching condition loss characterization and analysis involving an enhanced-mode (E-mode) GaN implemented in a conventional topology is investigated and veri?ed.
关键词： E-mode,WBG,Hard-switching,HEMT,DPT,Soft-switching,GaN
更新于2025-09-04 15:30:14
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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) - Design of Ultra-Wideband Bandpass (UWB) Filter with Enhanced Couplings by Using Lumped Capacitors
摘要： This paper presents a novel ultra-wideband bandpass (UWB) filter with enhanced input/output couplings by high quality lumped capacitors in place of traditional coupling methods. The filter consists of traditional stub-loaded dual-mode resonator and a pair of lumped capacitors, which symmetrically located at the input/output ports. Different from the technology of parallel-coupled microstrip lines in enhancing the capacitive couplings, this paper uses high quality ceramics trimmer capacitors to realize strong capacitive couplings at the input/output ports. A compact microstrip UWB filter designed by this method is simulated, fabricated and measured. The simulated and measured results are in good agreements, showing validity of the proposed method.
关键词： dual-mode resonator,capacitive couplings,lumped capacitors,Ultra-wideband (UWB) filter
更新于2025-09-04 15:30:14
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TWO-WAY MODIFIED WILKINSON POWER DIVIDER FOR UWB APPLICATIONS USING TWO SECTIONS OF UNEQUAL ELECTRICAL LENGTHS
摘要： This paper presents 2-way Power Divider (PD) for Ultra-Wideband (UWB) applications. The proposed power divider is realized using two cascaded sections of Wilkinson Power Divider (WPD) of equal characteristic impedances and unequal electrical lengths with inserted open stub to improve matching, isolation and to broaden the bandwidth. It is proved analytically using the “Even Odd Mode” analysis method and the ABCD matrix to obtain exact closed-form design equations. A detailed design methodology is introduced to facilitate the implementation without needing CAD optimization. To verify the proposed design methodology, a 2-way power divider is designed, fabricated on a Rogers RT/Duroid 5880 substrate and compared to other published 2-way microstrip power dividers. Measured data show good agreement with Electromagnetic (EM)-Circuit Co-Simulation, which proves the design equations and methodology. The proposed planar 2-way PD achieves an isolation ≥ 13.5 dB, input return loss ≥ 10 dB, output return loss ≥ 14.5 dB and exceeded insertion loss ≤ 0.9 dB (over the ?3 dB splitting ratio) through the whole UWB range from 3.1 GHz to 10.6 GHz. Furthermore, it has a compact area of 22 mm × 15 mm, which provides 50% enhancement over similar microstrip PD circuits while achieving better isolation and matching.
关键词： Power Divider (PD),Ultra-Wideband (UWB),ABCD Matrix,Wilkinson Power Divider (WPD),Even-Odd Mode Analysis
更新于2025-09-04 15:30:14
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A COMPACT TRIPLE-MODE BANDPASS HMSIW FILTER
摘要： A simple method for designing a triple-mode bandpass ?lter is presented in this paper. Triple-mode is achieved by using half-mode substrate integrated waveguide (HMSIW) cavity. Three perturbation metal vias were introduced for shifting resonant modes. The resonant frequencies of these modes can be adjusted by the location and the diameter of perturbation vias properly. In order to improve the out-of-band rejection, the CPW-to-SIW transition was added. A triple-mode HMSIW ?lter with the center frequency of 13 GHz was designed and fabricated. The measured fractional bandwidth is 35% with a transmission zero located at 20.4 GHz. Good agreement is observed between simulation and measurement.
关键词： perturbation vias,triple-mode bandpass filter,HMSIW,CPW-to-SIW transition
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - C-V Measurement under Different Frequencies and Pulse-mode Voltage Stress to Reveal Shallow and Deep Trap Effects of GaN HEMTs
摘要： In this work, the influence of interface traps at the Si3N4/ (GaN) /AlGaN interface and carbon-related buffer traps on AlGaN/GaN-on-silicon high electron mobility transistors (HEMTs) has been studied using high-frequency capacitance-voltage (HFCV) and quasi-static C-V (QSCV) measurement. The correlation between Ron degradation and two different traps distributions subjected to different operation conditions have been investigated. Deep-level traps from the hole-emission process of carbon-related buffer have been activated by high drain voltage under off-state in pulse-mode condition and shallow-level traps from interface states are observed with an increase in gate voltage under on-state.
关键词： Traps,GaN HEMTs,Pulse-mode Stress,C-V measurement
更新于2025-09-04 15:30:14
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Frequency Conversion in KTP Crystal and Its Isomorphs
摘要： We report the results of an analysis of the functional capabilities of the KTP crystal and its isomorphs for nonlinear-optical frequency conversion of all types of interactions in the transparency range of the crystal. The possibility of implementing angle, wavelength (frequency), and temperature-noncritical phase matching is shown.
关键词： temperature-noncritical mode,nonlinear crystals,frequency conversion,KTP and isomorphs,functional capabilities
更新于2025-09-04 15:30:14
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Development of the Full Package of Gyrotron Simulation Code
摘要： A complete code-package for gyrotron simulation to analyze its performance is under development in UNIST, Korea. We first time report the present status of the code-package named as UNIST Gyrotron Design Tool (UGDT). It can perform design simulations for gyrotron’s interaction cavity, RF window, and the essential mode calculations including the study of mode competition. We will discuss about its salient features, theory, numerical implementation, and its calculation result for 95 GHz UNIST Gyrotron. Moreover, we will validate its capability to perform the mode competition calculation for fundamental and second harmonic modes.
关键词： Harmonic operation,Mode competition,Gyrotron design code,Gyrotron
更新于2025-09-04 15:30:14