4,168 research outputs found
Design of Compact BPF and Planar Diplexer for UMTS using Embedded-scheme Resonator
A compact planar diplexer utilizing embedded-scheme resonator (ESR) is designed for universal mobile telecommunications system (UMTS). The ESR is formed by embedding interdigital resonators into an open loop resonator. Based on the proposed ESR, a narrowband bandpass filter suitable for diplexer design is proposed, fabricated and measured. The measured results demonstrate that the filter exhibits good transmission properties within band and high frequency selectivity. The rectangular area occupied by the filter has overall dimensions only 0.086λg by 0.105λg, promises good potential in wireless communication systems that require compact size and high encapsulation quality. Then, a compact planar diplexer operating at the TX-band of 1920-1980MHz and the RX-band of 2110-2170MHz, which is composed of a meander T-junction and two filters initially separately designed, is synthesized, simulated and measured. Both the simulated and measured results indicate that satisfied impedance matching and good isolation between two paths have been achieved
Compact and High Performance Dual-band Bandpass Filter Using Resonator-embedded Scheme for WLANs
A compact microstrip dual-band bandpass filter (DBBPF) with high selectivity and good suppression for wireless local area networks (WLANs) is proposed utilizing a novel embedded scheme resonator. Two passbands are produced by a pair of embedded half-wavelength meandered stepped-impedance resonator (MSIR) and a quadwavelength short stub loaded stepped-impedance resonator (SIR) separately. The resonator is fed by folded Tshaped capacitive source-load coupling microstrip feed line, and four transmission zeros are obtained at both sides of the bands to improve selectivity and suppression. Simultaneously, the size of the filter is extermely compact because embedding half-wavelength MSIR only changes the interior configuration of quad-wavelength SIR. To validate the design method, the designed filter is fabricated and measured. Both simulated and measured results indicate that good transmission property has been achieved
New Method for Numerically Solving the Chemical Potential Dependence of the Dressed Quark Propagator
Based on the rainbow approximation of Dyson-Schwinger equation and the
assumption that the inverse dressed quark propagator at finite chemical
potential is analytic in the neighborhood of , a new method for
obtaining the dressed quark propagator at finite chemical potential from
the one at zero chemical potential is developed. Using this method the dressed
quark propagator at finite chemical potential can be obtained directly from the
one at zero chemical potential without the necessity of numerically solving the
corresponding coupled integral equations by iteration methods. A comparison
with previous results is given.Comment: Revtex, 14 pages, 5 figure
Business Communication in the People's Republic of China
This is a seminal statement on the pre-eminent position held by business communication in China's largest business school—specializing in interna tional trade—the Beijing Institute of Foreign Trade. The authors provide some historical background, review three courses in business communica tion in China, summarize the method of instruction, and end with con cludions and opportunities for closer academic ties with China in making business communication a truly international discipline.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68578/2/10.1177_002194368302000103.pd
The dynamic dipole polarizabilities of the Li atom and the Be+ ion
The dynamic dipole polarizabilities for the Li atom and the Be+ ion in the 2s
and 2p states are calculated using the variational method with a Hylleraas
basis. The present polarizabilities represent the definitive values in the
non-relativistic limit. Corrections due to relativistic effects are also
estimated. Analytic representations of the polarizabilities for frequency
ranges encompassing the n=3 excitations are presented. The recommended
polarizabilities for ^7Li and ^9Be+ were 164.11 \pm 0.03 a.u. and 24.489 \pm
0.004 a.u.
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