An Electromigration and Thermal Model of Power Wires for a Priori High-Level Reliability Prediction

In this paper, a simple power-distribution electrothermal model including the interconnect self-heating is used together with a statistical model of average and rms currents of functional blocks and a high-level model of fanout distribution and interconnect wirelength. Following the 2001 SIA roadmap projections, we are able to predict a priori that the minimum width that satisfies the electromigration constraints does not scale like the minimum metal pitch in future technology nodes. As a consequence, the percentage of chip area covered by power lines is expected to increase at the expense of wiring resources unless proper countermeasures are taken. Some possible solutions are proposed in the paper

Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver

Metamaterial-Inspired Efficient Electrically Small Antenna

Abstract—Planar two-dimensional (2D) and volumetric threedimensional (3D) metamaterial-inspired efficient electrically-small antennas that are easy to design; are easy and inexpensive to build; and are easy to test; are reported, i.e., the EZ antenna systems. The proposed 2D and 3D electrical- and magnetic-based EZ antennas are shown to be naturally matched to a 50 source, i.e., without the introduction of a matching network. It is demonstrated numerically that these EZ antennas have high radiation efficiencies with very good impedance matching between the source and the antenna and, hence, that they have high overall efficiencies. The reported 2D and 3D EZ antenna designs are linearly scalable to a wide range of frequencies and yet maintain their easy-to-build characteristics. Several versions of the 2D EZ antennas were fabricated and tested. The measurement results confirm the performance predictions. The EZ antennas systems may provide attractive alternatives to existing electrically-small antennas. Index Terms—Antenna efficiency, antennas, electrically small antenna (ESA), metamaterials. I

Applications of Electromagnetic Principles in the Design and Development of Proximity Wireless Sensors

Sensors and sensing system are playing dominant roles in monitoring the health of infrastructure, such as bridges, power lines, gas pipelines, rail roads etc. Sensing modalities employing Surface Acoustic Waves (SAW), Electromagnetic (EM) and optical have been investigated and reported. Sensors that utilize the perturbation of EM fields as function of the change in the physical structural or material phenomenon are of particular interest because of their inherent synergy with electronic system and diagnostic techniques, e.g. Time Domain Reflectometry (TDR), Joint-Time-Frequency-Domain-Reflectometry (JTFDR). The focus of this work is to study and develop new sensing and monitoring concepts that are based on EM principles. First, the analyses, design and development of a static electric field type sensor are presented for application in embedded concrete moisture content measurement. The analytical formulation and results based on conformal mapping method for an interdigitated sensor clearly show the dependency of the field penetration depth and the inter-electrode capacitance on the electrode sizes and their spacings. It is observed that larger electrode size and small separation are needed in order to achieve substantially higher capacitance or large field penetration depth. A meander and a circular sensor are fabricated and tested to demonstrate concrete moisture content measurements that show that moisture content is a linear function of sensor interelectrode capacitance. Second, sub-wavelength dimension non-intrusive wave launchers are designed and tested that can launch TDR or JTFDR type broadband surface wave waveforms in the VHF-UHF bands in order to detect cable faults. Greater than 3:1 transmission bandwidth (100-300 MHz) is obtained with a cylindrical launcher on square orthogonal ground plane while with a CSW launcher more than an octave (100-240 MHz) bandwidth is achieved. Open circuit faults are detected using surface waves and TDR on two XLPE cables. Third, a new mathematical method is developed that can be used to determine the changes in the dielectric constant of a cable insulating material. By comparing the experimental JTFDR waveform signatures from a new and an aged cable, it is demonstrated that the change in the average dielectric constant of the insulation material can be estimated from the phase transfer functions obtained from the FFT of measured magnitude and phase responses. The experimental data obtained for two types of cables, XLPE and EPR show that the dielectric constant decreases with accelerated aging. Finally, JTFDR surface wave sensing method is developed and applied to determine the locations of aging related insulation damage in power cables. The comparative power spectral responses of conducted and non-intrusive surface wave JTFDR waveforms clearly show the resulting bandwidth reduction in the latter primarily because of the reflective nature of the coupling. It is demonstrated that with the help of a non-intrusive wave launcher and a 120 MHz Gaussian chirp waveform the location of aging related insulation damages can be detected. Experiments conducted show the cross-correlation peaks at subsequent aging intervals as the cable is aged inside a heat chamber

A Robust 43-GHz VCO in CMOS for OC-768 SONET Applications

In this paper, we present a 43-GHz LC-VCO in 0.13-/spl mu/m CMOS for use in SONET OC-768 optical networks. A tuned output buffer is used to provide 1.3 V/sub p-p/ (single-ended) into a 90-fF capacitive load as is required when the VCO is used in typical clock and data recovery (CDR) circuits. Phase noise is -90 dBc/Hz at a 1-MHz offset from the carrier; this meets SONET jitter specifications. The design has a tune range of 4.2%. The VCO, including output buffers, consumes 14 mA from a 1-V supply and occupies 0.06 mm/sup 2/ of die area. Modern CMOS process characteristics and the high center frequency of this design mean that the tank loss is not dominated by the integrated inductor, but rather by the tank capacitance. An area-efficient inductor design that does not require any optimization is used

Analysis And Design Of Low Profile Multiband Multifunctional Antenna Arrays

Light-weight phased array antennas for aerospace and mobile applications require utilizing the same antenna aperture to provide multiple functions with dissimilar radiation pattern specifications (e.g., multiband operation for communications and tracking). Multi-functional antennas provide advantages over aggregate antenna clusters by reducing space requirements, and can aid in the optimal placement of all required apertures to provide adequate isolation between channels. Furthermore, the combination of antenna apertures into a comgeometry mitigates co-site installation issues by addressing interference within the integrated radiator design itself as opposed to the extensive analysis which is required to configure multiple radiators in close proximity. The combination of multiple radiators into a single aperture can only be achieved with the proper selection of antenna topology and accompanying feed network design. This research proposes a new technique for the design of multiband arrays in which a comaperture is used. Highlighted by this method is the integration of a tri-band array comprised of an x-band (12 ghz) microstrip patch array on a superstrate above printed dual-band (1 and 2 ghz) slot loop antenna arrays in an octave-spaced lattice. The selection of a ground backing reflector is considered for improved gain and system packaging, but restricts the utility of the design principally due to the î›/4 depth of the ground plane. Therefore, a novel multiband high impedance surfaces (his) is proposed to load the slot apertures for reduced height. The novel techniques proposed here will enable the design of a low profile and conformal single aperture supporting multi-band and multi-functional operations

Piezoelectric energy harvesting solutions

This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions

Design and fabrication of filters based on surface acoustic wave devices

The aim of this thesis was to extend previous work to SAW resonator based wideband bandpass filters on LiNbO3 substrates. In order to accomplish this aim, it was necessary to: 1) apply coupling of modes (COM) theory 2) develop custom fabrication techniques for black LiNbO3 substrates 3) understand the critical issues in fabricating a wideband bandpass SAW filter. This thesis discusses the issues that must be addressed in order to achieve successful devices

A Reconfigurable Pseudohairpin Filter Based on MEMS Switches

This work presents a bandpass-reconfigurable planar pseudohairpin filter based on RF-MEMS switches. Hairpin-line structures are preferred to design microstrip filters because this class of filters offers a more compact size, and, in general, hairpin filters do not need ground connections for resonators. In this work, the U-shape resonators are arranged to obtain an interdigit capacitor to improve the coupling between the resonators. RF-MEMS switches modify the lengths of coupled resonators by adding microstrip segments to control the filter bandwidth, moving the center frequency and the return loss. An experimental hairpin tunable filter prototype based on RF-MEMS has been designed, fabricated, numerically and experimentally assessed, and compared concerning its tunability, quality factor, and capability with standard tunable filters based on PIN diodes. In conclusion, the tunable hairpin filter based on RF-MEMS switches offers the best performance in center frequency tuning range, compactness, and power consumption regarding reconfigurable filters based on standard PIN diodes switches. The obtained results are appealing and demonstrate the capabilities and potentialities of RF-MEMS to operate with the new communication standards that work at high microwave frequency bands