Packaging of RF Mems Switching Functions on Alumina Substrate

Recently the strong demands in wireless communication requires expanding development for the application of RF MEMS (Radio Frequency micro electro mechanical systems) sensing devices such as micro-switches, tunable capacitors because it offers lower power consumption, lower losses, higher linearity and higher Q factors compared with conventional communications components. To accelerate commercialisation of RF MEMS products, development for packaging technologies is one of the most critical issues should be solved beforehand.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

RF-MEMS Switched Varactors for Medium Power Applications

In RF (Radio Frequency) domain, one of the limitations of using MEMS (Micro Electromechanical Systems) switching devices for medium power applications is RF power. Failure phenomena appear even for 500 mW. A design of MEMS switched capacitors with an enhanced topology is presented in this paper to prevent it. This kind of device and its promising performances will serve to fabricate a MEMS based phase shifter able to work under several watts.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

Magnetic-field-dependent quasiparticle energy relaxation in mesoscopic wires

In order to find out if magnetic impurities can mediate interactions between quasiparticles in metals, we have measured the effect of a magnetic field B on the energy distribution function f(E) of quasiparticles in two silver wires driven out-of-equilibrium by a bias voltage U. In a sample showing sharp distributions at B=0, no magnetic field effect is found, whereas in the other sample, rounded distributions at low magnetic field get sharper as B is increased, with a characteristic field proportional to U. Comparison is made with recent calculations of the effect of magnetic-impurities-mediated interactions taking into account Kondo physics.Comment: 4 pages, 3 figures, to be published in Physical Review Letter

Influence of Magnetic Field on Effective Electron-Electron Interactions in a Copper Wire

We have measured in a copper wire the energy exchange rate between quasiparticles as a function of the applied magnetic field. We find that the effective electron-electron interaction is strongly modified by the magnetic field, suggesting that magnetic impurities play a role on the interaction processes.Comment: latex anthore.tex, 8 files, 6 figures, 7 pages in: Proceedings of the XXXVIth Rencontres de Moriond `Electronic Correlations: From Meso- to Nano-physics' Les Arcs, France January 20-27, 2001 [SPEC-S01/027

Developments in Constitutional Law: The 1988-89 Term

This article canvasses the major developments from the 1988-89 term of the Supreme Court of Canada. In terms of Charter jurisprudence there were major developments concerning equality rights, mobility rights, freedom of expression, and section 7. More generally, there were also important developments in the federal trade and commerce power and broad hints as to the Supreme Court\u27s leanings in relation to the federal spending power. There is clarification on how both federal and provincial laws affect federal undertakings, and re-affirmation of the ancillary nature of powers in relation to language. The Court reassesses the tests of when a provincial inferior tribunal oversteps the bounds created by section 96, and has an opportunity to consider again the jurisdiction of section 101 courts. The Court is also called upon to specify the extent of autonomy for denominational schools afforded section 93. Thus, the 1988-89 term is particularly comprehensive in relation to the Constitution Act, 1867, extending beyond the standard sections 91/92 issues

Manipulating the Quantum State of an Electrical Circuit

We have designed and operated a superconducting tunnel junction circuit that behaves as a two-level atom: the ``quantronium''. An arbitrary evolution of its quantum state can be programmed with a series of microwave pulses, and a projective measurement of the state can be performed by a pulsed readout sub-circuit. The measured quality factor of quantum coherence Qphi=25000 is sufficiently high that a solid-state quantum processor based on this type of circuit can be envisioned.Comment: 4 figures include

Voltage-induced Shapiro steps in a superconducting multi-terminal structure

When a superconducting tunnel junction at a finite voltage is irradiated with microwaves, the interplay between the alternating Josephson current and the ac field gives rise to steps in the dc current known as Shapiro steps. In this work we predict that in a mesoscopic structure connected to several superconducting terminals one can induce Shapiro-like steps in the absence of any external radiation simply by tuning the voltages of the leads. To illustrate this effect we make quantitative predictions for a three-terminal structure which comprises a diffusive superconductor-normal metal-superconductor junction and a tunneling probe, a set-up which can be realized experimentally.Comment: revtex4, 5 pages, 5 figures, to appear in Phys. Rev.

Dynamics of quasiparticle trapping in Andreev levels

We present a theory describing the trapping and untrapping of quasiparticles in the Andreev bound level of a single-channel weak link between two superconductors. We calculate the rates of the transitions between even and odd occupations of the Andreev level induced by absorption and emission of both photons and phonons. We apply the theory to a recent experiment [Phys. Rev. Lett. 106, 257003 (2011)] in which the dynamics of the trapping of quasiparticles in the Andreev levels of superconducting atomic contacts coupled to a Josephson junction was measured. We show that the plasma energy $h\nu_p$ of the Josephson junction defines a rather abrupt transition between a fast relaxation regime dominated by coupling to photons and a slow relaxation regime dominated by coupling to phonons. With realistic parameters the theory provides a semi-quantitative description of the experimental results.Comment: 11 pages, 9 figures. Accepted for publication in Physical Review