The scaling of microchip technologies has enabled large scale systems-on-chip (SoC). Network-on-chip (NoC) research addresses global communication in SoC, involving (i) a move from computation-centric to communication-centric design and (ii) the implementation of scalable communication structures. This survey presents a perspective on existing NoC research. We define the following abstractions: system, network adapter, network, and link to explain and structure the fundamental concepts. First, research relating to the actual network design is reviewed. Then system level design and modeling are discussed. We also evaluate performance analysis techniques. The research shows that NoC constitutes a unification of current trends of intrachip communication rather than an explicit new alternative.

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A survey of research and practices of Network-on-chip

Preface Introduction Conventional Coplanar Waveguide Conductor-Backed Coplanar Waveguide Coplanar Waveguide with Finite-Width Ground Planes Coplanar Waveguide Suspended Inside A Conducting Enclosure Coplanar Striplines Microshield Lines and Coupled Coplanar Waveguide Attenuation Characteristics of Conventional, Micromachined, and Superconducting Coplanar Waveguides Coplanar Waveguide Discontinuities and Circuit Elements Coplanar Waveguide Transitions Directional Couplers, Hybrids, and Magic-Ts Coplanar Waveguide Applications References Index

Coplanar waveguide circuits, components, and systems

The market for driver assistance systems based on millimeter-wave radar sensor technology is gaining momentum. In the near future, the full range of newly introduced car models will be equipped with radar based systems which leads to high volume production with low cost potential. This paper provides background and an overview of the state of the art of millimeter-wave technology for automotive radar applications, including two actual silicon based fully integrated radar chips. Several advanced packaging concepts and antenna systems are presented and discussed in detail. Finally measurement results of the fully integrated radar front ends are shown.

Millimeter-Wave Technology for Automotive Radar Sensors in the 77 GHz Frequency Band

We report on a promising approach for the label-free analysis of DNA molecules using direct probing of the binding state of DNA with electromagnetic waves at THz frequencies. Passive THz resonator devices based on planar waveguides are used as sample carriers and transducers for THz transmission analysis. In comparison to a formerly used free-space detection scheme, this method provides a drastically enhanced sensitivity enabling analysis down to femtomol levels. We examine the potential of our approach on biologically relevant DNA samples and demonstrate the detection of single base mutations on DNA molecules.

Integrated THz technology for label-free genetic diagnostics

We report the experimental and theoretical study of the dispersive behavior of surface plasmon polaritons (SPPs) on cylindrical metal surfaces in the terahertz frequency range. Time-domain measurements of terahertz SPPs propagating on metal wires reveal a unique structure that is inconsistent with a simple extrapolation of the high frequency portion of the dispersion diagram for SPPs on a planar metal surface, and also distinct from that of SPPs on metal nanowires observed at visible and near-infrared frequencies. The results are consistent with a numerical solution of Maxwell's equations, showing that the dispersive behavior of SPPs on a cylindrical metal surface at terahertz frequencies is quite different from that of SPPs on a flat surface. These findings indicate the increasing importance of skin effects for SPPs in the terahertz range, as well as the enhancement of such effects on curved surfaces.

Dispersion of surface plasmon polaritons on metal wires in the terahertz frequency range.

A quasi-TEM model of MMIC coplanar structures is presented. The elements of the distributed equivalent circuit are calculated by closed-form approximations and hence can easily be implemented into CAD packages. The effects of nonideal conductors are included as well as substrate loss and finite metallization thickness. The description holds for the entire quasi-TEM range, i.e. for typical MMIC geometries from DC to millimeter-wave frequencies. The validity of the model was checked by comparison to full-wave results. The errors for the effective dielectric constant and the characteristic impedance range below 5% for the attenuation typical values of 5-10% are found (maximum: 20%). >

Quasi-TEM description of MMIC coplanar lines including conductor-loss effects

A mode-matching analysis of lossy planar transmission lines is presented. This method uses a modified mode-matching technique developed for travelling-wave FET analysis. The metallic layers are treated in the same way as the remaining waveguide subregions, with each of them characterized by its complex dielectric constant. This leads to a fully self-consistent description of the conductor losses. In contrast to the usual perturbation methods, it includes metallic loss by a self-consistent description without any skin-effect approximation. The analysis holds for arbitrarily high losses and also for metallization dimensions smaller than the skin depth. The approach is validated by comparison with previous experimental and theoretical work. Monolithic microwave integrated circuit (MMIC) microstrip and coplanar lines are investigated. The variation in propagation characteristics for typical metallization thickness is studied and the consequences with regard to MMIC design are discussed. For the coplanar waveguides (CPWs) significant deviations compared to the conventional assumption of lossless zero-thickness strips are found. >

Full-wave analysis of conductor losses on MMIC transmission lines

A detailed investigation of flip-chip interconnects up to W-band frequencies is presented in this paper. In a coplanar 50-/spl Omega/ environment, different test structures were fabricated and measured to determine the electromagnetic characteristics of flip-chip multichip modules, such as detuning, reflection at the interconnect, and parasitic coupling. Electromagnetic simulation is used to explain the details behind the measured results. Key to high return loss at the interconnect is a small bump-pad area. Applying simple compensation structures, the frequency range of operation can be further extended. It is shown that a return loss beyond 20 dB in the frequency range up to 80 GHz is achievable along with excellent reproducibility. Measurements on detuning and isolation are also presented.

Theory and measurements of flip-chip interconnects for frequencies up to 100 GHz

This paper presents a detailed analysis of the stressing mechanisms for highly rugged low-noise GaN monolithic-microwave integrated-circuit amplifiers operated at extremely high input powers. As an example, a low-noise amplifier (LNA) operating in the 3-7-GHz frequency band is used. A noise figure (NF) below 2.3 dB is measured from 3.5 to 7 GHz with NF<1.8 dB between 5-7 GHz. This device survived 33 dBm of available RF input power for 16 h without any change in low-noise performance. The stress mechanisms at high input powers are identified by systematic measurements of an LNA and a single high electron-mobility transistor in the frequency and time domains. It is shown that the gate dc current, which occurs due to self-biasing, is the most critical factor regarding survivability. A series resistance in the gate dc feed can reduce this gate current by feedback, and may be used to improve LNA ruggedness

Analysis of the Survivability of GaN Low-Noise Amplifiers

Electromagnetic simulation and measurement data of flip-chip transitions are presented. First-order effects are identified and design criteria for millimeter-wave multichip interconnects are derived. Results cover chip detuning and bump geometry as well as simplified modeling. In a coplanar environment, the flip-chip scheme provides interconnects with excellent low-reflective properties. For conductor-backed structures, parasitic modes occur leading to unwanted crosstalk. These effects dominate the behavior so that overall performance of the flip-chip scheme can be evaluated properly only in conjunction with the actual motherboard packaging setup.

Wolfgang Heinrich

Papers

Quasi-TEM description of MMIC coplanar lines including conductor-loss effects

Full-wave analysis of conductor losses on MMIC transmission lines

Theory and measurements of flip-chip interconnects for frequencies up to 100 GHz

Analysis of the Survivability of GaN Low-Noise Amplifiers

Millimeter-wave characteristics of flip-chip interconnects for multichip modules