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This paper proposes use of traveling wave type excitation sources for the scattering analysis of RF SAW/BAW devices using the finite element method(FEM). By generating a single mode selectively, scattering behavior at arbitrary edges can be evaluated efficiently in frequency domain. After describing its detailed mechanism, two examples are presented for the use in SAW and BAW models. The results revealed...
Suppression of the SH-SAW response is mandatory to design TC SAW devices on θ degree rotated Y-cut LiNbO3. However, it is not easy because K2 for SH SAW changes rapidly with θ, and its optimal value in terms of the SH-SAW suppression is dependent on electrode and SiO2 thicknesses. The authors found that the optimal θ always locates close to θ where difference in velocities of two SAWs is minimum....
Design of side edges is one of the most important tasks for realization of high performance RF SAW/BAW devices. For the purpose, the authors proposed an FEM based technique where the specified mode is injected to the border under concern through a damping mechanism, and scattering coefficients are estimated from calculated BAW field [1]. Even though this technique is effective, its setup is too complicated...
This paper investigates piston mode operation (PMO) when two kinds of surface acoustic wave (SAW) exist and are coupled to each other. The extended thin plate model is used for the analysis. Firstly, a PMO condition is derived in an analytical and closed form from the model. It is found that PMO is possible without adding phase shifters when two SAW modes are coupled. Then, parameters defined in the...
This paper investigates influence of coupling between Rayleigh and SH SAWs on rotated Y-cut LiNbO3 to their electromechanical coupling. For the purpose, a COM model including the coupling between two SAWs is developed, and its validity is confirmed by comparison of its results with the FEM analysis. Then it is discussed how the coupling influences to their excitation in addition to propagation. After...
The piston mode operation (PMO) is quite effective for realization of spurious-free and low-loss SAW resonators. The scalar potential (SP) analysis indicates that “phase shifters” are necessary for PMO at edges of the acoustic aperture. Nakamura, et al., pointed out that for SAW resonators using SiO2/LiNbO3 structure, PMO is possible by simply removing SiO2 in the dummy electrode region [1]. This...
This paper describes perturbation analysis of nonlinear signal generation in radio frequency (RF) bulk acoustic wave (BAW) devices. Nonlinear constitutive equations with the h form are used where the electric flux density is an independent variable. In conventional ones with the e form, the electric flux density is a dependent variable. This choice makes generated nonlinear fields satisfy Gauss' law...
This paper investigates applicability of double raised borders to the piston mode film bulk acoustic resonator (FBAR). It is shown that it offers significant improvement of the quality factor at the antiresonance without sacrificing the spurious level when the structure is designed appropriately. This enhancement is attributed to the reduction of the mode-conversion and the increase of the reflection...
A new aviation proactive maintenance support system was put forward based on the Beidou satellite data link. The “Air-Ground” two-direction data processing method was adopted to carry out the on-line interpretation of flight parameters, the proactive maintenance support and the real-time operation of the safety monitoring system. The basic condition of proactive maintenance support, aircraft real-time...
In dynamic environment, for the supply chain with time-varying demand forecast accuracy, although the lead-time compression may raise forecast accuracy, it may produce crash costs. Manufacturer owns the true information of crash costs and tells higher costs to retailer in order to get more profit. This paper takes the above situations into consideration, develops a supply chain coordination model...
This paper systematically analyzed and optimized the operation parameters of low current 1T1R RRAM arrays. Considering both thermal and electrical field driven effects, a current and voltage joint verification strategy has been proposed. Highly uniform multilevel resistive switching performances with LRS resistance higher than 100kΩ and HRS resistance higher than 10MΩ were obtained on 130nm CMOS process...
Uncertainties in frequency regulations (FR) of generators and loads, and their effects on probabilistic power flow (PPF) analysis are addressed in this paper. The conventional PPF analysis is based on power flow model, without considering the frequency regulation. However, according to frequency regulation characteristics, generation outputs and load demand will respond to frequency deviation. Furthermore,...
Cloud computing promises high performance and cost-efficiency, however, most cloud infrastructures operate at low utilization which greatly adhere cost effectiveness. Previous works focus on seeking efficient virtual machine (VM) consolidation strategies to increase the utilization of virtual resources in production environment, while overlooking the under-utilization of backup virtual resources....
A novel kind of RF MEMS lateral extensional thin-film piezoelectric-on-silicon(TPoS) resonator with narrow tethers is proposed. The conventional three-layers supporting beams could be simplified to single material by utilizing different kinds of doping on the bulk structural silicon layer. Within the scope of the fabrication process allowed, the width of tethers could be decreased from 10µm to 2µm,...
The radial tunable periodic cusped magnet (RTPCM) focusing system is designed in this paper. It is shown that a radial divergent sheet beam with 1800V, 84.9mA can be transported smoothly through the drift tunnel with height of 0.36mm and length of 18.8mm focused by this RTPCM system.
A RRAM cell integrated with a selector was fabricated. The device with 1S1R structure has Pt/Al2O3/NbO2/TaOy/Ta2O5-x/Pt stacks. Al2O3 serves as the current compliance layer. NbO2 layer works as the threshold switching selector. TaOy is the base layer for resistive switching. The RRAM switching is based on the conduction filaments formed and ruptured in the Ta2O5-x layer. For the fabricated device,...
The radial sheet beam traveling wave tubes can work at the frequency of millimeter wave band, have the properties of high efficiency, broad bandwidth, miniaturized dimensions, and easily to be integrated and so on. The radial divergent sheet beam electron optical system with cylindrical emission surface is designed for the Ka band radial sheet beam traveling wave tubes in this paper. The radial divergent...
This paper presents a 0.22THz big beam-tunnel folded-waveguide (FWG) traveling-wave tube (TWT) with a phase-velocity taper. The big beam tunnel was applied in order to reduce the processing difficulty and increase the capability of the direct current power. And the input and output coupling structures and attenuator were simulated and the entire tube transmission characteristic was analyzed by employing...
This paper mainly introduces the study for 140 GHz folded waveguide (FWG) traveling wave tube (TWT) with big electron tunnel. Through the high frequency simulation software and 3-D particle in cell (PIC) simulation, we get the structural parameters. By using these parameters, we fabricate the whole vacuum electron device (VED), including the slow wave structure, magnetic focusing system, input and...
The radial divergent sheet beam electron optical system focused by a radial uniform magnetic field is designed in this paper. It is shown that the radial divergent sheet beam with size of 8 deg×0.23 mm, generated by the electron gun with 1700V, 151 mA, can stably pass through the beam drift tunnel with transverse size of 20 deg×0.52 mm and the length of 20 mm in a radial quasi-uniform magnetic field.
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