bluuebunny/crossref_metadata_2025 huggingface dataset:
A remote sensing technique for global monitoring of power plant CO2 emissions from space and related applications
Authors: Bovensmann H. , Buchwitz M. , Burrows J. P. , Reuter M. , Krings T. , Gerilowski K. , Schneising O. , Heymann J. , Tretner A. , Erzinger J.
Published: April 2010

Abstract. Carbon dioxide (CO2) is the most important anthropogenic greenhouse gas causing global warming. The atmospheric CO2 concentration increased by more than 30% since pre-industrial times – primarily due to burning of fossil fuels – and still continues to increase. Reporting of CO2 emissions is required by the Kyoto protocol. Independent verification of reported emissions, which are typially not directly measured, by methods such as inverse modeling of measured atmospheric CO2 concentrations is currently not possible globally due to lack of appropriate observations. Existing greenhouse gas observing satellites such as SCIAMACHY and GOSAT focus on advancing our understanding of natural CO2 sources and sinks. The obvious next step for future generation satellites is to also measure anthropogenic CO2 emissions. Here we present a promising satellite remote sensing technology based on spectroscopic measurements of reflected solar radiation in the short-wave infrared (SWIR) and near-infrared (NIR) spectral regions and show, using power plants as an example, that strong localized CO2 point sources can be detected and their emissions quantified. This requires mapping the CO2 column distribution at a spatial resolution of 2×2 km2 or better with a precision of about 0.5% (2 ppm) or better of the background column. We indicate that this can be achieved with existing technology. For a single satellite in sun-synchronous orbit with an across-track swath width of 500 km each power plant is overflown every 6 days or faster. Based on clear sky statistics we conservatively estimate that about one useful measurement per 1–2 months for a given power plant can typically be achieved. We found that the uncertainty of the retrieved power plant CO2 emission during a single satellite overpass is in the range 0.5–5 MtCO2/year – depending on observation conditions – which is about 2–20% of the CO2 emission of large power plants (25 Mt CO2/year). The investigated instrument aims at fulfilling all requirements for global regional-scale CO2 and CH4 surface flux inverse modeling. Using a significantly less demanding instrument concept based on a single SWIR channel we indicate that this also enables the monitoring of power plant CO2 emissions in addition to high-quality methane retrievals. The latter has already been demonstrated by SCIAMACHY. The discussed technology has the potential to significantly contribute to an independent verification of reported anthropogenic CO2 emissions and therefore could be an important component of a future global anthropogenic CO2 emission monitoring system. This is of relevance in the context of Kyoto protocol follow-on agreements but also allows to detect and monitor strong natural CO2 and CH4 emitters such as (mud) volcanoes.
A high-resolution mass spectrometer to measure atmospheric ion composition
Authors: Junninen H. , Ehn M. , Petäjä T. , Luosujärvi L. , Kotiaho T. , Kostiainen R. , Rohner U. , Gonin M. , Fuhrer K. , Kulmala M. , Worsnop D. R.
Published: April 2010

Abstract. In this paper we present recent achievements on developing and testing a tool to detect the composition of ambient ions in the mass/charge range up to 2000 Th. The instrument is an Atmospheric Pressure Interface Time-of-Flight Mass Spectrometer (APi-TOF, Tofwerk AG). Its mass accuracy is better than 0.002%, and the mass resolving power is 3000 Th/Th. In the data analysis, a new efficient Matlab based set of programs (tofTools) were developed, tested and used. The APi-TOF was tested both in laboratory conditions and applied to outdoor air sampling in Helsinki at the SMEAR III station. Transmission efficiency calibrations showed a throughput of 0.1–0.5% in the range 100–1300 Th for positive ions, and linearity over 3 orders of magnitude in concentration was determined. In the laboratory tests the APi-TOF detected sulphuric acid-ammonia clusters in high concentration from a nebulised sample illustrating the potential of the instrument in revealing the role of sulphuric acid clusters in atmospheric new particle formation. The APi-TOF features a high enough accuracy, resolution and sensitivity for the determination of the composition of atmospheric small ions although the total concentration of those ions is typically only 400–2000 cm-3. The atmospheric ions were identified based on their exact masses, utilizing Kendrick analysis and correlograms as well as narrowing down the potential candidates based on their proton affinities as well isotopic patterns. In Helsinki during day-time the main negative ambient small ions were inorganic acids and their clusters. The positive ions were more complex, the main compounds were (poly)alkyl pyridines and – amines. The APi-TOF provides a near universal interface for atmospheric pressure sampling, and this key feature will be utilized in future laboratory and field studies.
Novel SO2 spectral evaluation scheme using the 360–390 nm wavelength range
Authors: Bobrowski N. , Kern C. , Platt U. , Hörmann C. , Wagner T.
Published: April 2010

Abstract. Differential Optical Absorption Spectroscopy (DOAS) is a well established spectroscopic method to determine trace gases in the atmosphere. During the last decade, passive DOAS, which uses solar radiation scattered in the atmosphere as a light source, has become a standard tool to determine SO2 column densities and emission fluxes from volcanoes and other large sources by ground based as well as satellite measurements. For the determination of SO2 column densities, the structured absorption of the molecule in the 300–330 nm region (due to the A1B1←X1A1 transition) is used. However, there are several problems limiting the accuracy of the technique in this particular application. Here we propose to use an alternative wavelength region (360–390 nm) due to the spin-forbidden a3B2←X1A1 transition for the DOAS evaluation of SO2 in conditions where high SO2 column densities prevail. We show this range to have considerable advantages in such cases, in particular when the particle content of the plume is high and when measurements are performed at large distances from the area of interest.
CRISTA-NF measurements during the AMMA-SCOUT-O3 aircraft campaign
Authors: Weigel K. , Riese M. , Hoffmann L. , Hoefer S. , Kalicinsky C. , Knieling P. , Olschewski F. , Preusse P. , Stroh F. , Spang R. , Volk C. M.
Published: April 2010

Abstract. The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere – New Frontiers (CRISTA-NF) instrument successfully participated in the AMMA-SCOUT-O3 measurement campaign in July and August 2006. The instrument is mounted on the high-flying Russian research aircraft M55-Geophysica and measures limb-emissions in the mid-infrared region in the altitude range of about 6 to 21 km. We present a new retrieval scheme that was developed to obtain atmospheric temperature and trace gas fields with high vertical resolution (up to 500 m). Retrieval results are shown for temperature, water vapor (H2O), ozone (O3), nitric acid (HNO3), peroxyacetyl nitrate (PAN), carbon tetrachloride (CCl4), and aerosol extinction. Comparisons of temperature, O3, and H2O observations with corresponding in situ measurements on-board M55-Geophysica show reasonable agreement. In particular, CRISTA-NF observations in the vicinity of the aircraft resemble horizontal variations found in the in situ measurements better than corresponding ECMWF fields.
Spectral analysis of Floating Car Data
Authors: Gössel F. , Michler E. , Wrase B.
Published: April 2010

Abstract. Floating Car Data (FCD) are one important data source in traffic telematic systems. The original variable in these systems is the vehicle velocity. The paper analyses the measured value “vehicle velocity" by methods of information technology. Consequences for processing, transmission and storage of FCD under condition of limited resources are discussed. Starting point of the investigation is the analysis of spectral characteristics of velocity-time-profiles. The spectra are determined by the Discrete Fourier Transform (DFT) from measurement data and simulation data of a microscopic traffic model. One essential property of velocity-time-profiles is their low-pass characteristic. The resulting cut-off-frequency is comparatively small and depends on the traffic scenario. Conclusions concerning the necessary sample rate in FCD systems and the processing of raw data are discussed. Finally the transinformation of velocity-time-profiles is analysed. This results in similar values for an optimal sample rate of FCD systems under condition of limited transmission capacity.
Downlink beamforming concepts in UTRA FDD
Authors: Schacht M. , Dekorsy A. , Jung P.
Published: April 2010

Abstract. This article gives a comparison of beamforming concepts. Adaptive beamforming and fixed beam switching in WCDMA-FDD-mode are compared from a system level perspective, ordinary sectorization (three 120° sectors) serves as a basis for comparison. Pilot channels P-CPICH (Primary Common Pilot Channel) and S-CPICH (Secondary CPICH) are considered as additional interference. For adaptive beamforming channel estimation has to be based on the pilot bit sequence on DPCCH (Dedicated Physical Control Channel) which leads to degradation especially for high mobile velocities and large angular dispersions of the multipath channel.
Performance analysis of general purpose and digital signal processor kernels for heterogeneous systems-on-chip
Authors: von Sydow T. , Blume H. , Noll T. G.
Published: April 2010

Abstract. Various reasons like technology progress, flexibility demands, shortened product cycle time and shortened time to market have brought up the possibility and necessity to integrate different architecture blocks on one heterogeneous System-on-Chip (SoC). Architecture blocks like programmable processor cores (DSP- and GPP-kernels), embedded FPGAs as well as dedicated macros will be integral parts of such a SoC. Especially programmable architecture blocks and associated optimization techniques are discussed in this contribution. Design space exploration and thus the choice which architecture blocks should be integrated in a SoC is a challenging task. Crucial to this exploration is the evaluation of the application domain characteristics and the costs caused by individual architecture blocks integrated on a SoC. An ATE-cost function has been applied to examine the performance of the aforementioned programmable architecture blocks. Therefore, representative discrete devices have been analyzed. Furthermore, several architecture dependent optimization steps and their effects on the cost ratios are presented.
Broadband suppression of phase-noise with cascaded phase-locked-loops for the generation of frequency ramps
Authors: Musch T.
Published: April 2010

Abstract. The generation of analogue frequency ramps with non-fractional phase-locked-loops (PLL) is a cost effective way of linearising varactor controlled oscillators (VCO). In case that the VCO shows a high phase-noise level, a single non-fractional PLL is not able to suppress the phase-noise of the VCO sufficiently. The reason for this is the limited loopbandwidth of the PLL. In the field of precise measurements a high phase-noise level is mostly not tolerable. Examples of VCO-types with an extremely high phase noise level are integrated millimetre wave oscillators based on GaAs-HEMT technology. Both, a low quality factor of the resonator and a high flicker-noise corner frequency of the transistors are the main reason for the poor phase-noise behaviour. On the other hand this oscillator type allows a cost effective implementation of a millimetre-wave VCO. Therefore, a cascaded two-loop structure is presented that is able to linearise a VCO and additionally to reduce its phase-noise significantly.
Automated collection and dissemination of ionospheric data from the digisonde network
Authors: Reinisch B.W. , Galkin I. A. , Khmyrov G. , Kozlov A. , Kitrosser D.
Published: April 2010

Abstract. The growing demand for fast access to accurate ionospheric electron density profiles and ionospheric characteristics calls for efficient dissemination of data from the many ionosondes operating around the globe. The global digisonde network with over 70 stations takes advantage of the Internet to make many of these sounders remotely accessible for data transfer and control. Key elements of the digisonde system data management are the visualization and editing tool SAO Explorer, the digital ionogram database DIDBase, holding raw and derived digisonde data under an industrial-strength database management system, and the automated data request execution system ADRES.
A novel quasi-peak-detector for time-domain EMI-measurements
Authors: Krug F. , Braun S. , Russer P.
Published: April 2010

Abstract. In this paper, an advanced ultra-fast, broadband time domain EMI measurement system is described. Measurements were performed in the 30–1000MHz range. The digital signal processing of EMI measurements allows to emulate in real-time the modes of conventional analogous equipment, e.g. Peak-, Average-, RMS- and Quasi-Peak- Detector. With the presented time domain measurement system the measurement time can be reduced by a factor of 10. A novel signal recording routine for time-domain EMI (TDEMI) measurements and Quasi-Peak-Detection is described. Measurement results obtained from the investigation of a drillmachine, monitor and laptop obtained with the timedomain electromagnetic interference (TDEMI) measurement system are discussed. The results obtained with the described system have been compared with measurements performed with a conventional EMI receiver.
Comparison of ionospheric radio occultation CHAMP data with IRI 2001
Authors: Jakowski N. , Tsybulya K.
Published: April 2010

Abstract. GPS radio occultation measurements on board low Earth orbiting satellites can provide vertical electron density profiles of the ionosphere from satellite orbit heights down to the bottomside. Ionospheric radio occultation (IRO) measurements carried out onboard the German CHAMP satellite mission since 11 April 2001 were used to derive vertical electron density profiles (EDP’s) on a routine basis. About 150 vertical electron density profiles may be retrieved per day thus providing a huge data basis for testing and developing ionospheric models. Although the validation of the EDP retrievals is not yet completed, the paper addresses a systematic comparison of about 78 000 electron density profiles derived from CHAMP IRO data with the International Reference Ionosphere (IRI 2001). The results are discussed for quite different geophysical conditions, e.g. as a function of latitude, local time and geomagnetic activity. The comparison of IRO data with corresponding IRI data indicates that IRI generally overestimates the upper part of the ionosphere whereas it underestimates the lower part of the ionosphere under high solar activity conditions. In a first order correction this systematic deviation could be compensated by introducing a height dependence correction factor in IRI profiling.
Real-time ionospheric N(h) profile updating over Europe using IRI-2000 model
Authors: Buresova D. , Cander Lj. R. , Vernon A. , Zolesi B.
Published: April 2010

Abstract. In this paper a method for real-time updating of ionospheric electron density profile, N(h), over Europe using an ionospheric model and real-time measurements at ionosonde locations is presented. The N(h) profile update over European area has been simulated with the IRI-2000 ionospheric model and real-time N(h) profiles obtained from the EU COST271 Action Space Weather Database. Preliminary findings are shown for the geomagnetically quiet day on 4 May 2003 and disturbed day on 24 May 2002. Results are discussed in the context of real-time N(h) profile updating capabilities and effectiveness.
Computation of electrostatic fields in anisotropic human tissues using the Finite Integration Technique (FIT)
Authors: Motresc V. C. , van Rienen U.
Published: April 2010

Abstract. The exposure of human body to electromagnetic fields has in the recent years become a matter of great interest for scientists working in the area of biology and biomedicine. Due to the difficulty of performing measurements, accurate models of the human body, in the form of a computer data set, are used for computations of the fields inside the body by employing numerical methods such as the method used for our calculations, namely the Finite Integration Technique (FIT). A fact that has to be taken into account when computing electromagnetic fields in the human body is that some tissue classes, i.e. cardiac and skeletal muscles, have higher electrical conductivity and permittivity along fibers rather than across them. This property leads to diagonal conductivity and permittivity tensors only when expressing them in a local coordinate system while in a global coordinate system they become full tensors. The Finite Integration Technique (FIT) in its classical form can handle diagonally anisotropic materials quite effectively but it needed an extension for handling fully anisotropic materials. New electric voltages were placed on the grid and a new averaging method of conductivity and permittivity on the grid was found. In this paper, we present results from electrostatic computations performed with the extended version of FIT for fully anisotropic materials.
Examination of the demodulation effect of two-tone disturbances on nonlinear elements
Authors: Nitsch J. , Korovkin N. , Solovyeva E.
Published: April 2010

Abstract. The effect of two disturbing sources with close frequencies on a nonlinear circuit is investigated. It is shown that low-frequency oscillations occur in such a circuit. These low-frequency oscillations represent a significant threat to the electronic equipment, since standard filters do not suppress low-frequency harmonics. On the basis of Picard’s iterations the synthesis of a protection system against low-frequency oscillations is performed.
Coupling electromagnetic pulse-shaped waves into wire-like interconnection structures with a non-linear protection – Time domain calculations by the PEEC method
Authors: Wollenberg G. , Kochetov S. V.
Published: April 2010

Abstract. An interconnection system whose loads protected by a voltage suppressor and a low-pass filter against overvoltages caused by coupling pulse-shaped electromagnetic waves is analyzed. The external wave influencing the system is assumed as a plane wave with HPM form. The computation is provided by a full-wave PEEC model for the interconnection structure incorporated in the SPICE code. Thus, nonlinear elements of the protection circuit can be included in the calculation. The analysis shows intermodulation distortions and penetrations of low frequency interferences caused by intermodulations through the protection circuits. The example examined shows the necessity of using full-wave models for interconnections together with non-linear circuit solvers for simulation of noise immunity in systems protected by nonlinear devices.
Evaluation of Measurement Uncertainty of Radiated EMC Tests in Arbitrary Field Generators using Surface Currents on DUT
Authors: Schrader T. , Münter K. , Spitzer M. , Eulig N. , Enders A.
Published: April 2010

Abstract. We present a method for the evaluation of measurement uncertainty in radiated EMC tests. It is based on the measurement of surface current densities on a sphere, the results are compared to the surface current distribution on a sphere in a free-space environment obtained by numerical calculations. The free-space is considered to be a reference field generator. By this method we avoid burdening any systematic deviations of one particular (historic) method to any of the others. We evaluate the ratio J/E of the measured surface current density J and the measured empty electrical field strength E for both the reverberation chamber and the semi-anechoic chamber.
A Low-Cost Versatile Broadband (DC to K-Band) Planar 50Ω Termination
Authors: Olbrich M. O. , Biebl E. M.
Published: April 2010

Abstract. Numerous standard RF circuits like directional couplers, hybrids, amplitude modulators, oscillators, etc. require a 50Ω termination. Additionally, in several measurement scenarios, ports have to be terminated. Such terminations are preferable of the same waveguide type as the circuits to avoid degradation of their performance. In general, standard fabrication steps are desired as they are cost-effective. The straightforward solution is a 50Ω resistor shunted to ground by means of a via. Partial wraparound SMD resistors in a 0402 size have low parasitics making them applicable up to K-band. However, for RF, this combination suffers from the considerable inductive parasitics of the via. Different approaches to avoid the vias, with varying disadvantages exist. We analyzed the approach of broadband matching the non ideal viaresistor combination to 50Ω by means of a filter structure. The realization uses only standard design and fabrication methods. The design procedure can easily be adapted to arbitrary substrates and fabrication technologies. The assembled 50Ω termination was measured using TRL calibration with a VNA. Therefore its characteristics are determined in the intended plane and it can be directly included into a planar 50Ω circuit. The measured terminations showed a VSWR better than 1.34 within the whole band from DC to K-band, and within 57% of the band (including the 24GHz ISM band) the VSWR is better than 1.22.
Radiation Pattern Analysis of Antenna Systems for MIMO and Diversity Configurations
Authors: Klemp O. , Eul H.
Published: April 2010

Abstract. Multiple-input multiple-output (MIMO) antenna systems and antenna configurations for wideband multimode diversity rank among the emerging key technologies in next generation wireless communication systems. The analysis of such transmission systems usually neglects the influences of real antenna radiation characteristics as well as the influences of mutual coupling in a multielement antenna arrangement. Nevertheless, to achieve a detailed description of diversity gain and channel capacity by using several transmit- and receive antennas in a wireless link, it is essential to take all those effects into account. The expansion of the radiation fields in terms of spherical eigenmodes allows an analytical description of the antenna radiation characteristics and accounts for all the coupling effects in multielement antenna configurations. Therefore the radiation pattern analysis by spherical eigenmode expansion provides an efficient alternative to establish an analytical approach in the calculation of envelope correlation or channel capacity.
Time-Domain Techniques for Computation and Reconstruction of One-Dimensional Profiles
Authors: Rahman M. , Marklein R.
Published: April 2010

Abstract. This paper presents a time-domain technique to compute the electromagnetic fields and to reconstruct the permittivity profile within a one-dimensional medium of finite length. The medium is characterized by a permittivity as well as conductivity profile which vary only with depth. The discussed scattering problem is thus one-dimensional. The modeling tool is divided into two different schemes which are named as the forward solver and the inverse solver. The task of the forward solver is to compute the internal fields of the specimen which is performed by Green’s function approach. When a known electromagnetic wave is incident normally on the media, the resulting electromagnetic field within the media can be calculated by constructing a Green’s operator. This operator maps the incident field on either side of the medium to the field at an arbitrary observation point. It is nothing but a matrix of integral operators with kernels satisfying known partial differential equations. The reflection and transmission behavior of the medium is also determined from the boundary values of the Green's operator. The inverse solver is responsible for solving an inverse scattering problem by reconstructing the permittivity profile of the medium. Though it is possible to use several algorithms to solve this problem, the invariant embedding method, also known as the layer-stripping method, has been implemented here due to the advantage that it requires a finite time trace of reflection data. Here only one round trip of reflection data is used, where one round trip is defined by the time required by the pulse to propagate through the medium and back again. The inversion process begins by retrieving the reflection kernel from the reflected wave data by simply using a deconvolution technique. The rest of the task can easily be performed by applying a numerical approach to determine different profile parameters. Both the solvers have been found to have the ability to deal with different types of slabs and incident electromagnetic pulses. Slabs having continuous and discontinuous relative permittivity have already been tested successfully. The tested electromagnetic pulses are a Dirac, Gaussian and sinusoidal pulse. Due to sampling, the resolution of the system also plays a significant role in obtaining better outputs from this scheme.
Digital Component Separator for future W-CDMA-LINC Transmitters implemented on an FPGA
Authors: Gerhard W. , Knöchel R.
Published: April 2010

Abstract. This paper presents the implementation of a Digital-Component-Separator (DCS) for a LINC-transmitter (linear amplification using nonlinear components) on an FPGA (field programmable gate array). It investigates and estimates the bandwidth requirements for such a LINC system. The influence of bandwidth limitations on a digitally based LINC-transmitter for W-CDMA utilization is studied by simulations. Furthermore a LINC transmitter is proposed which employs a flexible image-reject- or a direct up-conversion-architecture for transmission of single or combined multi-carrier/channel W-CDMA signals using the phase-modulation approach. The sampling frequency can be chosen at a value up to 32 times (122.88MHz) the symbol rate of the W-CDMA chip rate of 3.84Mbits/s. Measurement results for a LINC transmitter are presented and discussed.
A 8X Oversampling Ratio, 14bit, 5-MSamples/s Cascade 3-1 Sigma-delta Modulator
Authors: Yin Y. , Klar H. , Wennekers P.
Published: April 2010

Abstract. A 14-b, 5-MHz output-rate cascaded 3-1 sigma-delta analog-to-digital converters (ADC) has been developed for broadband communication applications, and a novel 4th-order noise-shaping is obtained by using the proposed architecture. At a low oversampling ratio (OSR) of 8, the ADC achieves 91.5dB signal-to-quantization ratio (SQNR), in contrast to 71.8dB of traditional 2-1-1 cascaded sigma-delta ADC in 2.5-MHz bandwidth and over 80dB signal-to-noise and distortion (SINAD) even under assumptions of awful circuit non-idealities and opamp non-linearity. The proposed architecture can potentially operates at much more high frequencies with scaled IC technology, to expand the analog-to-digital conversion rate for high-resolution applications.
Measured Response of Local, Mid-range and Far-range Discontinuities of Large Metal Groundplanes using Time Domain Techniques
Authors: Schrader T. , Münter K. , Battermann S. , Garbe H.
Published: April 2010

Abstract. This work describes a method to detect and to quantify any local or mid-range discontinuity on extended flat metal planes. Often these planes are used for antenna calibration (open area test site - OATS) or the plane could be the ground of a semi-anechoic chamber used in Electromagnetic Compatibility (EMC) testing. The measurement uncertainty of antenna calibration or EMC testing depends on the groundplane's quality, which can be accessed using this method. A vector network analyzer with time-domain option is used to determine the complex-valued input scattering parameter S11,F of an aperture antenna in a monostatic setup. S11,F contains the information desired about the discontinuities and is measured in the frequency domain with high dynamic range. But only after a linear filtering utilizing the Chirp-Z-Transform the obtained time-domain signal S11,T evidence of local and mid-range discontinuities.
Hybridverfahren zur EMV-Analyse elektrischer Leitungen über geschlitztem Grund
Authors: ter Haseborg J. R. , Brüns H.-D. , Singer H.
Published: April 2010

Abstract. Die Betrachtung niedrig geführter elektrischer Leitungen über leitendem Grund stellt besondere Anforderungen an die numerische Feldanalyse. Insbesondere für Fälle ungleichförmiger Leitungsführung oder ungleichförmigen Grunds werden Verfahren benötigt, die eine effektive EMV-Analyse zulassen. Die Verwendung von volldiskretisierten Modellen erfordert aufwändige Diskretisierungen, große Ressourcen und hohe Rechenzeiten. Daher werden Möglichkeiten gesucht, die effektive Leitungstheorie auf Anordnungen anzuwenden, deren direkte Berechnung in klassischer Betrachtungsweise nicht möglich ist. In der vorliegenden Arbeit wird ein Hybridverfahren vorgestellt, um den Einfluss von Schlitzen unterhalb von Leitungen in einer approximativen EMV-Analyse zu untersuchen. Hierzu dient neben der Leitungstheorie zur Berechnung des Leiterstroms eine momententheoretische Simulation auf Basis von magnetischen Linienströmen.
Timing violations due to VDD/VSS bounce
Authors: Eireiner M. , Henzler S. , Berthold J. , Pacha C. , Georgakos G. , Schmitt-Landsiedel D.
Published: April 2010

Abstract. The effect of power supply noise in on-chip power grids and its implications on the path delay in digital circuits is examined. The simulation results show that IR-Drop and the resulting path delay are strongly affected by the layout of the circuit. Power grid design measures to reduce IR-Drop, as well as their area and performance implications are discussed.
Ultra Low Power Bandgap Strom- und Spannungsquellen in CMOS-Technologie für integrierte drahtlose Systeme
Authors: Fedtschenko T. , Kokozinski R. , Kolnsberg S.
Published: April 2010

Abstract. In modernen drahtlosen Systemen sind niedriger Stromverbrauch und das Betreiben bei niedriger Spannung (Low Voltage Operation) von entscheidender Bedeutung. Dabei ist für viele elektronische Anwendungen eine genaue Spannungs- bzw. Stromreferenz notwendig. Aus diesem Grund werden an eine Referenzquelle hohe Anforderungen bezüglich ihrer Temperatur- und Langzeitstabilität gestellt, was gleichzeitig schwierig mit den "Low-Power" Anforderungen zu vereinbaren ist. Besonders für die auf passiven Transpondern basierenden RFID-Systeme, bei denen die Energieversorgung der Schaltung aus dem Hochfrequenzträgersignal gewonnen wird, stellt die Erzeugung einer genauen Spannungsreferenz ein Problem dar. Vor allem die Spannungsstabilität und die Unabhängigkeit von Temperatur- und Prozessschwankungen bereiten große Schwierigkeiten. In diesem Artikel wird das Design einer CMOS Bandgap Strom- und Spannungsreferenz, realisiert in einer 0,25 μm CMOS-Prozess-Technologie, mit 2,5 V Versorgungsspannung vorgestellt. Die entwickelte Schaltung hat eine Stromaufnahme von 50 μA bei einer Genauigkeit von 1% im Temperaturbereich von –40°C bis 125°C. Ein Testchip wurde in die Fertigung eingespeist. Ausgehend von einem Überblick über bekannte Realisierungen von Bandgap-Schaltungen wird die Besonderheit der neu entwickelten Low-Power Schaltung vergleichend gegenübergestellt.
A 10 bit very low-power CMOS SAR-ADC for capacitive micro-mechanical pressure measurement in implants
Authors: Bechen B. , Weiler D. , Boom T. v. d. , Hosticka B. J.
Published: April 2010

Abstract. This paper presents the development of a 10 bit very low-power CMOS SAR-ADC to be used in medical implants. The first part discusses the principle schematic and the requirements for component matching and the comparator of the ADC. Additionally, the measurement results of a fabricated test chip will be given. The second part of this paper discusses the possibility of direct on-chip implementation of a capacitive pressure sensor in a switched-capacitor SAR-ADC.
Modelling of the parametric yield in decananometer SRAM-Arrays
Authors: Fischer Th. , Nirschl T. , Lemaitre B. , Schmitt-Landsiedel D.
Published: April 2010

Abstract. In today's decananometer (90 nm, 65 nm, ...), CMOS technologies variations of device parameters play an ever more important role. Due to the demand for low leakage systems, supply voltage is decreased on one hand and the transistor threshold voltage is increased on the other hand. This reduces the overdrive voltage of the transistors and leads to decreasing read and write security margins in static memories (SRAM). In addition, smaller dimensions of the devices lead to increasing variations of the device parameters, thus mismatch effects increase. It can be shown that local variations of the transistor parameters limit the functionality of circuits stronger than variations on a global scale or hard defects. We show a method to predict the yield for a large number of SRAM devices without time consuming Monte Carlo simulations in dependence of various parameters (Vdd, temperature, technology options, transistor dimensions, ...). This helps the designer to predict the yield for various system options and transistor dimensions, to choose the optimal solution for a specific product.
Propagation models for high sites in urban areas
Authors: Hecker A. , Neuland M. , Kuerner T.
Published: April 2010

Abstract. Analyses of results from commonly used propagation models applied to UMTS Ultra High Sites in urban environments are presented. Differences between predicted and measured values for a site in Nuernberg are calculated as a function of the distance between base station and mobile station and as a function of the angle of incidence. An assessment of the validity range of the different propagation models is done. Furthermore, an analysis of the accuracy of the classification of building data is presented.
Multi-frequency sensor for remote measurement of breath and heartbeat
Authors: Jelen M. , Biebl E. M.
Published: April 2010

Abstract. Remote measurement of breath and heartbeat is desirable in many situations. It avoids the discomfort resulting from electrodes applied on the skin for long-term patients or during sports acvtivities. Also, surveillance of high security areas or finding survivors of disasters are interesting applications. Common methods identify the movement of heart and thorax by using the range resolution provided by UWB pulse radar systems. In this paper a low-cost approach is presented, that is based on detection of movement by means of Doppler radar sensors. Combining three sensors working in the ISM bands at 433 MHz, 2.4 GHz and 24 GHz, the presence of persons was reliably detected and the frequency of breath and heartbeat was measured.
Vergleich der Exposition der Bevölkerung durch digitale und analoge Rundfunksender
Authors: Schubert M. , Bornkessel C. , Wuschek M. , Schmidt P.
Published: April 2010

Abstract. Dieser Beitrag fasst die Ergebnisse eines Projektes zusammen, das vom Bundesamt für Strahlenschutz und dem Ministerium für Umwelt, Naturschutz und Reaktorsicherheit (BMU) im Rahmen des Deutschen Mobilfunk Forschungsprogramms (DMF) gefördert wurde. Hintergrund der Studie ist die Untersuchung der Auswirkung der Umstellung von der analogen auf die digitale terrestrische Rundfunkübertragung in Deutschland auf die Exposition der Bevölkerung.
Energy-efficient topology control for wireless sensor networks using online battery monitoring
Authors: Behrens C. , Bischoff O. , Lueders M. , Laur R.
Published: April 2010

Abstract. This paper presents a first approach towards cooperative energy management in wireless sensor networks using online battery monitoring. Using a standard platform for wireless sensor networks, a simple concept for measuring the battery voltage on the mote with little additional hardware is shown. This is used for modelling of the battery discharge behaviour of Li-Ion batteries and deriving the remaining lifetime under given environmental conditions. As an application example this model can be incorporated into a topology control scheme for optimized network lifetime under variable environmental conditions.
Power supply network design: a case study driven approach
Authors: Eireiner M. , Henzler S. , Missal T. , Berthold J. , Schmitt-Landsiedel D.
Published: April 2010

Abstract. A study, based on product related scenarios, on power supply integrity issues is conducted. The effectiveness of specific design parameters depends strongly on the expected loading of the power distribution grid. Therefore, the commonly used approach to only use an even current distribution can lead to non-optimal power grid designs. For power grid optimization, a problem reduction from quadratic to linear order is presented. Simulations in a System-on-Chip (SoC) environment show, that power supply integrity mainly depends on the placing of the cores within the SoC die.
Obstacle-based self-calibration techniques for the determination of the permittivity of liquids
Authors: Rolfes I.
Published: April 2010

Abstract. In this contribution, different obstacle-based self-calibration techniques for the measurement of the dielectric properties of liquids are investigated at microwave frequencies. The liquid under test is contained inside a waveguide, which is connected to the ports of a vector network analyzer. The permittivity of the liquid is characterized on the basis of the measured scattering parameters. In order to extract the material parameters precisely and to eliminate systematic errors of the setup, calibration measurements have to be performed. For this purpose, different self-calibration methods based on the displacement of an obstacle are considered. The presented methods differ in that way, that either transmission and reflection measurements or purely reflection measurements are performed. All these methods have in common that the material parameters are already calculable within a so-called self-calibration procedure. Thus, a full two-port calibration of the whole setup is not necessary. Furthermore, the methods can be realized effectively in a practical setup having the advantage that a rearrangement of the setup is not needed for the material parameter measurements and that the liquid under investigation can pass continuously through the measurement cell. This might be of interest for the application in an industrial process, enabling the continuous flow of the material while the parameter characterization can take place at the same time.
Energy modelling in sensor networks
Authors: Schmidt D. , Krämer M. , Kuhn T. , Wehn N.
Published: April 2010

Abstract. Wireless sensor networks are one of the key enabling technologies for the vision of ambient intelligence. Energy resources for sensor nodes are very scarce. A key challenge is the design of energy efficient communication protocols. Models of the energy consumption are needed to accurately simulate the efficiency of a protocol or application design, and can also be used for automatic energy optimizations in a model driven design process. We propose a novel methodology to create models for sensor nodes based on few simple measurements. In a case study the methodology was used to create models for MICAz nodes. The models were integrated in a simulation environment as well as in a SDL runtime framework of a model driven design process. Measurements on a test application that was created automatically from an SDL specification showed an 80% reduction in energy consumption compared to an implementation without power saving strategies.
Numerical modeling of the equatorial electrojet UT-variation on the basis of the model GSM TIP
Authors: Klimenko M. V. , Klimenko V. V. , Bryukhanov V. V.
Published: April 2010

Abstract. In the presented work the results of numerical modeling of the UT-variation of the equatorial electrojet, executed on the basis of the model GSM TIP are presented, taking into account the dynamo electric fields generated by thermospheric winds in a current-carrying layer of the ionosphere at heights 80–175 km above a surface of the Earth. To the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP), developed in WD IZMIRAN, a new block for the calculation of electric fields in the ionosphere has been added. In this block the solution of the three-dimensional equation describing the conservation law of the full current in the Earth's ionosphere is reduced to the solution of the two-dimensional equation by integration along geomagnetic field lines. Calculations of parameters of the near-Earth space plasmas have been executed for quiet equinoctial conditions on 22 March 1987 during the minimum of solar activity. It has been shown, that there is a distinct semidiurnal harmonic in the diurnal behavior of the linear density of the equatorial electrojet with maxima at 23:00 UT and 15:00 UT, as well as with minima at 06:00 UT and 20:00 UT. The greatest and smallest values of the peak intensity of the equatorial electrojet with respect to the diurnal behavior can differ by a factor of two. The longitudinal extent of the area of the equatorial electrojet does hardly show any UT-variation, but the greatest longitudinal extent is at 06 UT. With the growth of the peak intensity of the equatorial electrojet its latitudinal extent also increases (on ~5–10°) a little. At the same time the equatorial electrojet in the maxima of intensity has approximately an identical width, whereas in the minima the electrojet is narrow in the morning and wide in the afternoon. As for the surface density of the equatorial electrojet, its UT-variation is much weaker and equals ~1–3 A/km2 and the peak intensity is equal ~15–20 A/km2. The latitudinal extent of the surface density of the equatorial electrojet is maximal at 23:00 UT and 15:00 UT and minimal at 06:00 UT and 20:00 UT.
Analysis of quasi-optical power combiners by vector field measurements at 150 GHz
Authors: Judaschke R. , Weinzierl J.
Published: April 2010

Abstract. A Two-dimensional quasi-optical power dividing/combining circuit has been experimentally investigated at 150 GHz. It consists of a rectangular horn antenna array as receiving/transmitting unit and a dual offset reflector setup to match the radiated field(s) to the pattern of the receiving antenna(s). To verify both design and adjustment of the quasi-optical circuit, electric field scans have been performed in selected planes and volumes of the setup. To measure the spatial electric field distribution, a vector field measurement system has been developed which operates in the frequency range between 148 GHz and 152 GHz. Excellent agreement between calculated and measured results for a horn antenna array approve the predicted results calculated under the physical optics approximation. Measured power dividing/combining efficiency of the passive structure of 63% for an inter-element spacing of 10$ \\lambda$ indicates that the power combining principle is a suitable method up to submillimeter wavelengths.
On the statistics of differential phases in C-band weather radar
Authors: Otto T. , Chandra M.
Published: April 2010

Abstract. Differential phases open a new parameter in polarimetric weather radar data analysis. In polarimetric S-matrices measured at the linear polarisation bases (vertical and horizontal) there exist basically three differential phases namely the differential propagation phase and two co-to-crosspolar phases. In this paper we shall investigate the statistics of differential propagation phase and co-to-crosspolar phases in weather radar data recorded with the C-band weather radar of DLR, Wessling.
Time domain reflectrometry measurements using a movable obstacle for the determination of dielectric profiles
Authors: Will B. , Gerding M. , Schultz S. , Schiek B.
Published: April 2010

Abstract. Microwave techniques for the measurement of the permittivity of soils including the water content of soils and other materials, especially TDR (time domain reflectometry), have become accepted as routine measurement techniques. This summary deals with an advanced use of the TDR principle for the determination of the water content of soil along a probe. The basis of the advanced TDR technique is a waveguide, which is inserted into the soil for obtaining measurements of the effective soil permittivity, from which the water content is estimated, and an obstacle, which can mechanically be moved along the probe and which acts as a reference reflection for the TDR system with an exactly known position. Based on the known mechanical position of the reference reflection, the measured electrical position can be used as a measure for the effective dielectric constant of the environment. Thus, it is possible to determine the effective dielectric constant with a spatial resolution given by the step size of the obstacle displacement. A conventional industrial TDR-system, operating in the baseband, is used for the signal generation and for the evaluation of the pulse delay time of the obstacle reflection. Thus, a cost effective method for the acquisition of the dielectric measurement data is available.
Efficient passive network description of IC conducted emission models for model reduction
Authors: Ludwig S. , Radić-Weissenfeld Lj. , Mathis W. , John W.
Published: April 2010

Abstract. This article adresses the model reduction of IC conducted emission models. A method to efficiently deal with the high number of independent sources in IC conducted emission models, which are a strong limitation for model order reduction, is presented. A network alteration is proposed, which allows for a much higher model reduction than standard approaches. The system of the altered network can be more efficiently reduced with standard model order reduction algorithms in order to speed up frequency-simulations. Synthesising the reduced system into a passive electrical network enables fast time-simulations to be made with circuit simulators. The whole procedure is validated by reducing an example of an IC conducted emission model of an 32 Bit microcontroller.
Results and limits in the 1-D analytical modeling for the asymmetric DG SOI MOSFET
Authors: Cobianu O. , Glesner M.
Published: April 2010

Abstract. This paper presents the results and the limits of 1-D analytical modeling of electrostatic potential in the low-doped p type silicon body of the asymmetric n-channel DG SOI MOSFET, where the contribution to the asymmetry comes only from p- and n-type doping of polysilicon used as the gate electrodes. Solving Poisson's equation with boundary conditions based on the continuity of normal electrical displacement at interfaces and the presence of a minimum electrostatic potential by using the Matlab code we have obtained a minimum potential with a slow variation in the central zone of silicon with the value pinned around 0.46 V, where the applied VGS voltage varies from 0.45 V to 0.95 V. The paper states clearly the validity domain of the analytical solution and the important effect of the localization of the minimum electrostatic potential value on the potential variation at interfaces as a function of the applied VGS voltage.