IN-SITU APPROACH FOR CHARACTERIZATION AND MODELING OF TRANSPONDER PACKAGING TECHNIQUES IN RADIO FREQUENCY INDENTIFICATION SYSTEMS

In a typical Radio Frequency Identification system, the tag-reader communication is the most important characteristic of success or failure. In this system, the tag represents the weakest link in the equation and must be selected with great care. It is also important to recognize that a passive RFID tag derives its power from the RF energy generated by the reader. In turn, it communicates to the reader by modulation of the incident RF energy to create a backscatter signal, where any power loss between the antenna and the integrated circuit chip limits the maximum distance from which the tag can be read. Because the typical assembly flow of the RFID labels requires multiple steps, different assembly methodologies are being used to lower the final cost of the RFID label. Packaged parasitic components can significantly degrade the performance of the RFID tags. Today, the most insidious problem is the loss of energy due to the mismatch between the antenna and the IC chip. The final cost and fabrication requirements for the RFID tag impose a set of criteria on the assembly of the tag, where the typical methods for extracting and characterizing parasitic components of the packaging are not feasible. This research develops the theoretical mechanism for measuring and modeling the packaging parasitic components of the passive Ultra High Frequency RFID tags. The research is based on proven antenna theory and antenna measurement methods, which in turn will provide a benchmark for the current and future assembly methods for manufacturing of the RFID labels

Self-excited Oscillations of Charge-Spin Accumulation Due to Single-electron Tunneling

We theoretically study electronic transport through a layer of quantum dots connecting two metallic leads. By the inclusion of an inductor in series with the junction, we show that steady electronic transport in such a system may be unstable with respect to temporal oscillations caused by an interplay between the Coulomb blockade of tunneling and spin accumulation in the dots. When this instability occurs, a new stable regime is reached, where the average spin and charge in the dots oscillate periodically in time. The frequency of these oscillations is typically of the order of 1GHz for realistic values of the junction parameters

Cooling of a suspended nanowire by an AC Josephson current flow

We consider a nanoelectromechanical Josephson junction, where a suspended nanowire serves as a superconducting weak link, and show that an applied DC bias voltage an result in suppression of the flexural vibrations of the wire. This cooling effect is achieved through the transfer of vibronic energy quanta first to voltage driven Andreev states and then to extended quasiparticle electronic states. Our analysis, which is performed for a nanowire in the form of a metallic carbon nanotube and in the framework of the density matrix formalism, shows that such self-cooling is possible down to a level where the average occupation number of the lowest flexural vibration mode of the nanowire is $\sim 0.1$.Comment: 4 pages, 3 figure

Voltage-driven superconducting weak link as a refrigerator for cooling of nanomechanical vibrations

We consider a new type of cooling mechanism for a suspended nanowire acting as a weak link between two superconductive electrodes. By applying a bias voltage over the system, we show that the system can be viewed as a refrigerator for the nanomechanical vibrations, where energy is continuously transferred from the vibrational degrees of freedom to the extended quasiparticle states in the leads through the periodic modulation of the inter-Andreev level separation. The necessary coupling between the electronic and mechanical degrees of freedom responsible for this energy-transfer can be achieved both with an external magnetic or electrical field, and is shown to lead to an effective cooling of the vibrating nanowire. Using realistic parameters for a suspended nanowire in the form of a metallic carbon nanotube we analyze the evolution of the density matrix and demonstrate the possibility to cool the system down to a stationary vibron population of $\sim 0.1$. Furthermore, it is shown that the stationary occupancy of the vibrational modes of the nanowire can be directly probed from the DC current responsible for carrying away the absorbed energy from the vibrating nanowire.Comment: 10 pages, 4 figure

Superconductive pumping of nanomechanical vibrations

We demonstrate that a supercurrent can pump energy from a battery that provides a voltage bias into nanomechanical vibrations. Using a device containing a nanowire Josephson weak link as an example we show that a nonlinear coupling between the supercurrent and a static external magnetic field leads to a Lorentz force that excites bending vibrations of the wire at resonance conditions. We also demonstrate the possibility to achieve more than one regime of stationary nonlinear vibrations and how to detect them via the associated dc Josephson currents and we discuss possible applications of such a multistable nanoelectromechanical dynamics.Comment: 4 pages, 5 figure

Single-electron shuttle based on electron spin

A nanoelectromechanical device based on magnetic exchange forces and electron spin flips induced by a weak external magnetic field is suggested. It is shown that this device can operate as a new type of single-electron "shuttle" in the Coulomb blockade regime of electron transport

Nonequilibrium and quantum coherent phenomena in the electromechanics of suspended nanowires (Review Article)

Strong coupling between electronic and mechanical degrees of freedom is a basic requirement for the operation of any nanoelectromechanical device. In this Review we consider such devices and in particular investigate the properties of small tunnel-junction nanostructures that contain a movable element in the form of a suspended nanowire. In these systems, electrical currents and charge can be concentrated to small spatial volumes resulting in strong coupling between the mechanics and the charge transport. As a result, a variety of mesoscopic phenomena appear, which can be used for the transduction of electrical currents into mechanical operation. Here we will in particular consider nanoelectromechanical dynamics far from equilibrium and the effect of quantum coherence in both the electronic and mechanical degrees of freedom in the context of both normal and superconducting nanostructures

Non-Equilibrium and Quantum Coherent Phenomena in the Electromechanics of Suspended Nanowires

Strong coupling between electronic and mechanical degrees of freedom is a basic requirement for the operation of any nanoelectromechanical device. In this Review we consider such devices and in particular investigate the properties of small tunnel-junction nanostructures that contain a movable element in the form of a suspended nanowire. In these systems, electrical current and charge can be concentrated to small spatial volumes resulting in strong coupling between the mechanics and the charge transport. As a result, a variety of mesoscopic phenomena appear, which can be used for the transduction of electrical currents into mechanical operation. Here we will in particular consider nanoelectromechanical dynamics far from equilibrium and the effect of quantum coherence in both the electronic and mechanical degrees of freedom in the context of both normal and superconducting nanostructures.Comment: 20 pages, 13 figures, figures update

Is nitric oxide (NO) produced by invertebrate neurons?

NADPH-DIAPHORASE (NADPHd) is known to be identical to nitric oxide (NO) synthase in the mammalian nervous system, and is therefore used as a marker of NO-producing neurones. Using the histochemical reaction for NADPHd, we searched for such neurones in a selection of invertebrates. Special emphasis was given to molluscs. No selective neuronal staining was found in representatives of coelenterates, turbellarians, nematodes and urochordates. In all annelids, arthropods and molluscs examined, with the exception of a chiton, specific neurones were selectively stained. The reaction was particularly strong in pulmonate molluscs where scattered positive neurones were found in various ganglia and clustered symmetrically in the paired buccal ganglia. Biochemical assay of NO synthase in osphradia of the gastropod mollusc Lymnaea stagnalis revealed a formation of citrullin that was inhibited by the specific NO synthase N[omega]-nitro-L-arginine (NO2Arg). Both histochemical and biochemical methods indicate that NO can be used as a signal molecule by specific neurones in advanced invertebrates