Addressable time division multiplexer system /cable and connector study/ Final report

Reliability studies of single interrogation and single data cables used in prototype addressable time division multiplexer syste

Design and Analysis of Bow-tie Antennas for GPR Applications

Ground penetrating radar (GPR) is a non-destructive testing (NDT) technology, which uses electromagnetic (EM) techniques to map the buried structures in the shallow sub-surface. The efficiency of the GPR system significantly depends on the antenna performance as the signal has to propagate through lossy and inhomogeneous media. The GPR antennas should possess a low frequency of operation for more depth of penetration, ultra-wide band (UWB) performance for high resolution, high gain and efficiency for increasing the receiving power, minimal ringing, compact and lightweight for ease of GPR surveying. Bow-tie antennas are widely used as it can provide most of the above mentioned antenna performances. Though a number of researchers have carried out their research work for the design and development of the Bow-tie antennas for the GPR applications, still there is ample of scopes for the improvement of this antenna to achieve compactness and lightweight, reduced end-fire reflections, better gain and directivity, high radiation efficiency, etc. In this work, two improved Bow-tie antennas for the GPR applications have been proposed. A compact resistive loaded Bowtie antenna is designed and investigated which can provide an impedance bandwidth of 167% (0.4 - 4.5 GHz) with reduced end-fire reflections. The compactness is achieved by using a thin sheet of graphite for the resistive loading instead of using volumetric electromagnetic absorbing materials. The end-fire reflections are minimized by blending the sharp corners of the Bowtie antenna. However, the radiation efficiency and gain of the antenna are degraded significantly due to resistive loading which has been in the second proposed antenna by using an improved RC-loading scheme. The improved and compact RC-loaded Bowtie antenna with metamaterial based planar lens is designed and investigated which can operate over a UWB bandwidth of 3.71GHz (0.29 GHz - 4.5 GHz). This provides a maximum gain of 12.4 dB and maximum radiation efficiency of 94 % throughout the operating band. An improvement in the gain of 5 dB in the bore side direction is achieved by using a modified meta-material lens. The performance of both the designed antennas is investigated in the temperature varying environment and GPR scenario at the simulation level. A comparative analysis of the designed antennas with the other reported antennas indicates that the proposed antennas are advantageous for the GPR applications

Optimum design of structures of composite materials in response to aerodynamic noise and noise transmission

Elastic wave propagation and attenuation in a model fiber matrix was investigated. Damping characteristics in graphite epoxy composite materials were measured. A sound transmission test facility suitable to incorporate into NASA Ames wind tunnel for measurement of transmission loss due to sound generation in boundary layers was constructed. Measurement of transmission loss of graphite epoxy composite panels was also included

Determining Enclosure Breach Electromagnetically

A structure breach may be determined. A sensor, provided in the structure, may be driven with a constant frequency signal. The sensor may comprise a first conductive element and a second conductive element. The first conductive element may be substantially parallel with the second conductive element. A standing wave pattern may be induced on the sensor by the constant frequency signal reflecting off a termination point of the sensor. A least one characteristic of the sensor caused by the voltage standing wave pattern may be measured. A breach occurrence in the structure may be determined when the measured at least one characteristic varies from a previously determined value by a predetermined amount. The first conductive element and the second conductive element may be sandwiched between two layers comprising the structure. The structure may comprise a shipping container floor. The detected breach may comprise an opening greater than nine square inches.Georgia Tech Research Corporatio

The Quantum Socket: Three-Dimensional Wiring for Extensible Quantum Computing

Quantum computing architectures are on the verge of scalability, a key requirement for the implementation of a universal quantum computer. The next stage in this quest is the realization of quantum error correction codes, which will mitigate the impact of faulty quantum information on a quantum computer. Architectures with ten or more quantum bits (qubits) have been realized using trapped ions and superconducting circuits. While these implementations are potentially scalable, true scalability will require systems engineering to combine quantum and classical hardware. One technology demanding imminent efforts is the realization of a suitable wiring method for the control and measurement of a large number of qubits. In this work, we introduce an interconnect solution for solid-state qubits: The quantum socket. The quantum socket fully exploits the third dimension to connect classical electronics to qubits with higher density and better performance than two-dimensional methods based on wire bonding. The quantum socket is based on spring-mounted micro wires the three-dimensional wires that push directly on a micro-fabricated chip, making electrical contact. A small wire cross section (~1 mmm), nearly non-magnetic components, and functionality at low temperatures make the quantum socket ideal to operate solid-state qubits. The wires have a coaxial geometry and operate over a frequency range from DC to 8 GHz, with a contact resistance of ~150 mohm, an impedance mismatch of ~10 ohm, and minimal crosstalk. As a proof of principle, we fabricated and used a quantum socket to measure superconducting resonators at a temperature of ~10 mK.Comment: Main: 31 pages, 19 figs., 8 tables, 8 apps.; suppl.: 4 pages, 5 figs. (HiRes figs. and movies on request). Submitte

Cryogenic Applications of Commercial Electronic Components

We have developed a range of techniques useful for constructing analog and digital circuits for operation in a liquid Helium environment (4.2K), using commercially available low power components. The challenges encountered in designing cryogenic electronics include finding components that can function usefully in the cold and possess low enough power dissipation so as not to heat the systems they are designed to measure. From design, test, and integration perspectives it is useful for components to operate similarly at room and cryogenic temperatures; however this is not a necessity. Some of the circuits presented here have been used successfully in the MUSTANG and in the GISMO camera to build a complete digital to analog multiplexer (which will be referred to as the Cryogenic Address Driver board). Many of the circuit elements described are of a more general nature rather than specific to the Cryogenic Address Driver board, and were studied as a part of a more comprehensive approach to addressing a larger set of cryogenic electronic needs

Handbook of recommended practices for the determination of liquid monopropellant rocket engine performance

The design, installation, and operation of systems to be used for directly measuring quantities of fundamental importance to the determination of monopropellant thruster performance is described. Areas covered include: (1) force and impulse measurement; (2) propellant mass usage and flow measurement; (3) pressure measurement; (4) temperature measurement; (5) exhaust gas composition measurement; and (6) data reduction and performance determination