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Electromagnetic (EM) analysis for inhomogeneous penetrable structures relies on the formulation of volume integral equations (VIEs) in integral equation approach and time-domain VIEs (TDVIEs) are required for transient interaction with the structures. The TDVIEs are usually solved by combining the method of moments (MoM) with well-designed basis function in spatial domain and a march-on-in-time (MOT)...
Vacuum surface flashover switches based on polymers of polyimide (PI), polymethyl methacrylate (PMMA), and monomer cast Nylon as well as fused quartz are respectively designed and tested under condition of charge time 30 μs. The experimental results show that the PI switches are of the highest breakdown voltage and lifetime among the three types of polymers. For breakdown voltage of 416 kV, which...
The effects of fluorination on the vacuum surface flashover voltage (Uf) of polyimide (PI) are researched. The experimental results show that as the degree of fluorination increases, the Uf of PI firstly increases and then decreases, the highest Uf in the experiments is increased by up to 21 % compared with untreated PI sample. The results of Fourier-transform infrared spectroscopy (FTIR) and X-ray...
Dielectric Response Analysis of power transformer is widely used in a number of field tests and research projects. Both Dielectric Frequency Response (DFR) and Polarization and Depolarization Current (PDC) combined with proper paper-oil modeling are able to give more reliable condition assessment of power transformers. Power factor/dissipation factor test at power frequency (50/60 Hz) usually exhibits...
The general regularities of the electric surface flashover threshold (Ef) of polymers immersed in transformer oil and the polymers' bulk breakdown threshold (EBD) versus pulse width (τ) are obtained respectively by summarizing the experimental data in literatures. Those regularities are that Ef is proportional to τ−1 and that EBD is proportional to τ−1 when τ is smaller than 30 ns, when τ is larger...
This paper presents an analytical model to estimate the motional resistance for partial air gap capacitively-transduced MEMS resonators. This model serves as a link between the well formulated analytical models for conventional air gap and internal dielectric transduction schemes, thereby helping decide which scheme is optimal for a given design frequency. Using this model, we simulate and experimentally...
This paper presents a fabrication process to manufacture air-gap capacitively-transduced RF MEMS resonators. 2-port measurements show motional impedance (Rx) < 1.3 k?? and quality factor (Q) > 65,000 at 223 MHz in vacuum. The fabrication process involves depositing a dual-layer spacer of 10 nm of SiO2 and 90 nm of hafnia via atomic layer deposition (ALD) followed by oxide release. Nanometer...
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