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Abstract-A novel dual-wideband microstrip bandpass filter (BPF) with improved upper-stopband performance is presented. With the use of some special structures such as E-shaped microstrip SteppedImpedance Resonator (SIR) and input-output cross-coupling feed structure, this filter can generate five transmission zeros which are beneficial for improving its frequency selectivity and upper-stopband performance. Finally the microstrip dual-wideband BPF has been simulated, fabricated and measured. Measurement results show that the two passbands are centered at 3.7 GHz and 5.8 GHz with the fractional bandwidth of 31% and 13% respectively. Meanwhile more than 50% relative upper-stopband bandwidth with 20 dB rejection has been realized. The simulated and measured results are in good agreement.

Dual-frequency capacitive discharges: Effect of low-frequency current on electron distribution function Phys. Plasmas 12, 053501 (2005); 10.1063/1.1888325Numerical study of argon ions transported across the sheath in electron cyclotron resonance discharges

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The electron energy distribution function (EEDF), predicted by the Boltzmann equation solver BOLSIG+ based on the two-term approximation, is introduced into the fluid model for simulating the high-power microwave (HPM) breakdown in argon, nitrogen, and air, and its validity is examined by comparing with the results of particle-in-cell Monte Carlo collision (PIC/MCC) simulations as well as the experimental data. Numerical results show that, the breakdown time of the fluid model with the Maxwellian EEDF matches that of the PIC/MCC simulations in nitrogen; however, in argon under high pressures, the results from the Maxwellian EEDF were poor. This is due to an overestimation of the energy tail of the Maxwellian EEDF in argon breakdown. The prediction of the fluid model with the BOLSIG+ EEDF, however, agrees very well with the PIC/MCC prediction in nitrogen and argon over a wide range of pressures. The accuracy of the fluid model with the BOLSIG+ EEDF is also verified by the experimental results of the air breakdown.

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Abstract-An ultra-wideband (UWB) power divider is designed in this paper. The UWB performance of this power divider is obtained by using a tapered microstrip line that consists of exponential and elliptic sections. The coarse grained parallel micro-genetic algorithm (PMGA) and CST Microwave Studio are combined to achieve an automated parallel design process. The method is applied to optimize the UWB power divider. The optimized power divider is fabricated and measured. The measured results show relatively low insertion loss, good return loss, and high isolation between the output ports across the whole UWB (3.1-10.6 GHz).

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