オンチップ設計に向けた磁性膜によるノイズ抑制機構に関する研究

Tohoku University石山和志課

On the Transport Capability of LAN Cables in All-Analog MIMO-RoC Fronthaul

Centralized Radio Access Network (C-RAN) architecture is the only viable solution to handle the complex interference scenario generated by massive antennas and small cells deployment as required by next generation (5G) mobile networks. In conventional C-RAN, the fronthaul links used to exchange the signal between Base Band Units (BBUs) and Remote Antenna Units (RAUs) are based on digital baseband (BB) signals over optical fibers due to the huge bandwidth required. In this paper we evaluate the transport capability of copper-based all-analog fronthaul architecture called Radio over Copper (RoC) that leverages on the pre-existing LAN cables that are already deployed in buildings and enterprises. In particular, the main contribution of the paper is to evaluate the number of independent BB signals for multiple antennas system that can be transported over multi-pair Cat-5/6/7 cables under a predefined fronthauling transparency condition in terms of maximum BB signal degradation. The MIMO-RoC proves to be a complementary solution to optical fiber for the last 200m toward the RAUs, mostly to reuse the existing LAN cables and to power-supply the RAUs over the same cable

Development of a Hybrid Photo-Diode and its Front-End Electronics for the BTEV Experiment

This paper describes the development of a 163-channel Hybrid Photo-Diode (HPD) to be used in the RICH Detector for the BTEV Experiment. This is a joint development project with DEP, Netherlands. It also reports on the development of associated front-end readout electronics based on the va_btev ASIC, undertaken with IDEAS, Norway. Results from bench tests of the first prototypes are presented.Comment: Presented at Fourth International Workshop on RICH Detectors, Pylos Greece, June, 2002; to appear in the proceedings. (5 pages, 4 figures

JRA3 Electromagnetic Calorimeter Technical Design Report

This report describes the design of the prototype for an Silicon Tungsten electromagnetic calorimeter with unprecedented high granularity to be operated in a detector at the International Linear Collider (ILC). The R&D for the prototype is co-funded by the European Union in the FP6 framework within the so called EUDET project in the years 2006-2010. The dimensions of the prototype are similar to those envisaged for the final detector. Already at this stage the prototype features a highly compact design. The sensitive layers, the Very Front End Electronics serving 64 channels per ASIC and copper plates for heat draining are integrated within 2000 μm

Exclusion Limits on the WIMP-Nucleon Cross-Section from the First Run of the Cryogenic Dark Matter Search in the Soudan Underground Lab

The Cryogenic Dark Matter Search (CDMS-II) employs low-temperature Ge and Si detectors to seek Weakly Interacting Massive Particles (WIMPs) via their elastic scattering interactions with nuclei. Simultaneous measurements of both ionization and phonon energy provide discrimination against interactions of background particles. For recoil energies above 10 keV, events due to background photons are rejected with >99.99% efficiency. Electromagnetic events very near the detector surface can mimic nuclear recoils because of reduced charge collection, but these surface events are rejected with >96% efficiency by using additional information from the phonon pulse shape. Efficient use of active and passive shielding, combined with the the 2090 m.w.e. overburden at the experimental site in the Soudan mine, makes the background from neutrons negligible for this first exposure. All cuts are determined in a blind manner from in situ calibrations with external radioactive sources without any prior knowledge of the event distribution in the signal region. Resulting efficiencies are known to ~10%. A single event with a recoil of 64 keV passes all of the cuts and is consistent with the expected misidentification rate of surface-electron recoils. Under the assumptions for a standard dark matter halo, these data exclude previously unexplored parameter space for both spin-independent and spin-dependent WIMP-nucleon elastic scattering. The resulting limit on the spin-independent WIMP-nucleon elastic-scattering cross-section has a minimum of 4x10^-43 cm^2 at a WIMP mass of 60 GeV/c^2. The minimum of the limit for the spin-dependent WIMP-neutron elastic-scattering cross-section is 2x10^-37 cm^2 at a WIMP mass of 50 GeV/c^2.Comment: 37 pages, 42 figure

Enhancements in Dielectric Response Characterization of Insulation Materials

The increasing demand of integrating various renewable energy recourses in power system requires extensive use of power electronic solutions, such as HVDC and FACTS, as these techniques allow energy conversion between different frequencies and serves to stabilize the network. Consequently, electric stresses other than traditional 50/60 Hz sinusoidal voltage stress are acting on high voltage insulation materials. Therefore, a need for fast and accurate characterization methods, which can be used to study the influence on insulation materials of different types of voltage waveforms, has arisen. Dielectric response measurement is one commonly used non-destructive insulation test technique and has more than 100 years of history. Limitations like precision of the testing voltage waveform, high demand on a stable testing environmental condition, intricate specimen-electrode preparation, severe electrode geometric influences, etc., are however restraining the use of such measurements. In this project, several methods that are based on the Arbitrary Waveform Impedance Spectroscopy (AWIS) technique have been developed to enable fast and more accurate solid dielectric characterization. A test setup that is based on the AWIS technique can be optimized by implementing several techniques such as voltage divider, voltage follower, shielding box, etc., to reduce the measurement noise and to avoid crosstalk between adjacent signals. By utilizing optimized harmonic limited waveforms in the AWIS test setup, dielectric responses over a wide frequency spectrum can be determined simultaneously without degradation by signal aliasing. This also enables monitoring of the dielectric properties under fast changing test conditions as a source of systematic error is eliminated when all frequencies are obtained at the same time and at the same conditions. An air reference method and a contact-free electrode arrangement are described in this work to enhance the dielectric characterization accuracy by avoiding contact problems at the electrodes. It is shown that by performing a calibration with electrode gap filled with air under the same conditions as the material is tested, the air reference method can improve the measurement accuracy substantially. This type of approach also eliminates the need of a detailed model of the analog measurement circuit. In conjunction with the contact-free measurements, the approach allows for avoiding complicated and time-consuming specimen preparation procedures. The measurement methodology as well as the electrode arrangement and error estimation are presented and evaluated using different dielectric response instruments and materials. To improve the accuracy of dielectric permittivity, two methods are suggested in this work by either compensating or shielding the electrode setup from undesired geometric influences. One approach is to estimate a correction factor from a finite element method (FEM) model to improve the accuracy. The other approach uses a shielding guard electrode to avoid the geometric influence on measurement. Measurements of several PET films are used as an example to illustrate the use of correction factors in the application of contact free measurement. The latter method is only verified in FEM calculation

Electromagnetic Interference and Compatibility

Recent progress in the fields of Electrical and Electronic Engineering has created new application scenarios and new Electromagnetic Compatibility (EMC) challenges, along with novel tools and methodologies to address them. This volume, which collects the contributions published in the “Electromagnetic Interference and Compatibility” Special Issue of MDPI Electronics, provides a vivid picture of current research trends and new developments in the rapidly evolving, broad area of EMC, including contributions on EMC issues in digital communications, power electronics, and analog integrated circuits and sensors, along with signal and power integrity and electromagnetic interference (EMI) suppression properties of materials

Microwave Package Design for Superconducting Quantum Processors

Solid-state qubits with transition frequencies in the microwave regime, such as superconducting qubits, are at the forefront of quantum information processing. However, high-fidelity, simultaneous control of superconducting qubits at even a moderate scale remains a challenge, partly due to the complexities of packaging these devices. Here, we present an approach to microwave package design focusing on material choices, signal line engineering, and spurious mode suppression. We describe design guidelines validated using simulations and measurements used to develop a 24-port microwave package. Analyzing the qubit environment reveals no spurious modes up to 11GHz. The material and geometric design choices enable the package to support qubits with lifetimes exceeding 350 {\mu}s. The microwave package design guidelines presented here address many issues relevant for near-term quantum processors.Comment: 15 pages, 9 figure