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Fernández Pantoja, M. (author), Yarovoy, A.G. (author), Rubio Bretones, A. (author), González García, S. (author)This paper presents a procedure to extend the methods of moments in time domain for the transient analysis of thin-wire antennas to include those cases where the antennas are located over a lossy half-space. This extended technique is based on the reflection coefficient (RC) approach, which approximates the fields incident on the ground...journal article 2009
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Kooij, R.E. (author), Klos, V.B. (author), Godana, B.E. (author), Nicolai, F.P. (author), Ahmed, O.K. (author)Nowadays various digital television services are available. However, the user of these services experiences longer delays than the traditional analog TV while switching from channel to channel. The digital TV operator usually displays a black screen with the channel number during zapping. However, it could be interesting for the TV viewer, if...journal article 2009
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Budiarjo, I. (author)Cognitive Radio is a new paradigm in the wireless communications. It puts the intelligence and awareness dimension to the radio communication system. A Cognitive Radio system will be aware of the changing condition in its environment. The awareness in this thesis is related to the spectrum and the channel stipulation. By intelligent learning and...doctoral thesis 2009
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Figueras i Ventura, J. (author)The impact of the increase in anthropogenic aerosols on the global climate and the precipitation cycle is not yet fully understood. One of the reasons for that is the lack of sound measurements. In particular, high temporal and spatial resolution measurements of precipitation, coupled with measurements from other instruments, would be desired to...doctoral thesis 2009
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Budko, N.V. (author)Analytical solutions are presented for the electromagnetic radiation by an arbitrary pulsed source into a homogeneous time-varying background medium. In the constant-impedance case an explicit radiation formula is obtained for the synchronous permittivity and permeability described by any positive function of time. As might be expected, such a...journal article 2009
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Simeoni, M. (author), Lager, I.E. (author), Coman, C.I. (author), Roedener, A.G. (author)A method for ensuring polarization agility in conjunction with beam steering in planar array antennas is proposed. It relies on interleaving two subarrays with orthogonal, linear polarizations that, together, can generate arbitrary polarization states: adjustable linear, elliptical, and left- or right-handed circular. The complexity of the...journal article 2009
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Peddemors, A.J.H. (author)In the past several years, personal mobile devices have developed rapidly as versatile computing platforms, capable of installing and running many different applications. Often, these devices are equipped with multiple (wireless) network interfaces supporting internet access through one or more networks. The availability of these networks is...doctoral thesis 2009
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Rizvi, U.H. (author), Janssen, G.J.M. (author), Weber, J.H. (author)In this letter, closed-form expressions for the bit error rate of M-ary pulse amplitude modulated signal constellations as a function of the analog-to-digital converter word length, the signal-to-noise ratio and the fading distribution, are derived. These results allow for a rapid and accurate evaluation of the system performance when the analog...journal article 2009
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De Hoop, A.T. (author), Abubakar, A. (author), Habashy, T.M. (author)The contrast-source stress-velocity integral-equation formulation of three-dimensional time-domain elastodynamic scattering problems is discussed. A novel feature of the formulation is a tensor partitioning of the relevant dynamic stress and the contrast source volume density of deformation rate. The partitioning highlights several features...journal article 2009
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Wang, H. (author)Our society depends more strongly than ever on large networks such as transportation networks, the Internet and power grids. Engineers are confronted with fundamental questions such as “how to evaluate the robustness of networks for a given service?”, “how to design a robust network?”, because networks always affect the functioning of a service....doctoral thesis 2009
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Lager, I.E. (author), Trampuz, C. (author), Simeoni, M. (author), Ligthart, L.P. (author)An effective and robust strategy for concurrently designing the transmit and receive antennas of a frequency-modulated, continuos-wave radar is discussed. The aperture architecture is based on the use of non-periodic, interleaved sub-arrays. Deterministic element placement is employed for ensuring design efficiency. The procedure yields...journal article 2009
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De Hoop, A.T. (author), Jiang, L. (author)The response of a thin, high-contrast, finely layered structure with dielectric and conductive properties to an incident, pulsed, electromagnetic field is investigated theoretically. The fine layering causes the standard spatial discretization techniques to solve Maxwell's equations numerically to be practically inapplicable. To overcome this...journal article 2009
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Tanyer-Tigrek, F.M. (author), Tran, D.P. (author), Lager, I.E. (author), Ligthart, L.P. (author)An optimized coplanar waveguide fed quasimagnetic printed antenna for ultra wideband applications is described. A parameter study, motivated by a design procedure, allowed a substantial increase in the return-loss operational bandwidth. The numerically predicted performance was validated by means of physical measurements of fabricated samples....journal article 2009
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Ruggiano, M. (author), Stolp, E. (author), Van Genderen, P. (author)Orthogonal frequency division multiplexing (OFDM) waveforms offer strong advantages for integrated communication and radar systems. However, they exhibit inherent high-range sidelobes after matched filtering when standard communication constellation symbols are used for the coding of the carriers. Consequently, they require filtering at the...journal article 2009
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Pawelczak, P. (author), Pollin, S. (author), So, H.S.W. (author), Bahai, A.R.S. (author), Prasad, R.V. (author), Hekmat, R. (author)In this paper, different control channel (CC) implementations for multichannel medium access control (MAC) algorithms are compared and analyzed in the context of opportunistic spectrum access (OSA) as a function of spectrum-sensing performance and licensed user activity. The analysis is based on a discrete Markov chain model of a subset of...journal article 2009
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Doerr, C. (author), Grunwald, D. (author), Sicker, D.C. (author)In a network deployment, a cognitive radio will have to perform two fundamental tasks. First, each cognitive radio needs to optimize its internal operation, and second, it needs to derive a configuration that will enable and optimize communication with other nodes in the network. This latter requirement, however, relies on knowledge about the...journal article 2009
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Van Genderen, P. (author), Kovalenko, V. (author)Detection in most surveillance radars is based on the condition of point targets against a more or less homogeneous background. Currently, the resolution of many new types of radar is increasing, at least in the range dimension. Therefore many objects can no longer be considered as points. Also as a consequence, the background is becoming more...journal article 2009
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Babur, G. (author)The thesis consists of two parts. The first part is devoted to the theory of dual-orthogonal polarimetric radar signals with continuous waveforms. The thesis presents a comparison of the signal compression techniques, namely correlation and de-ramping methods, for the dual-orthogonal sophisticated signals. The novel time-frequency representation...doctoral thesis 2009
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Kleiberg, T.J. (author)During the past two decades the Internet has been widely deployed and integrated into the society, radically altering the way people communicate and exchange information. Although the Internet was intended as a research network between few a institutions in the United States, it has grown to take a central role in day-to-day communications and...doctoral thesis 2009
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Hoogeboom, P. (author), Van Vliet, F. (author)Under the auspices of the European Microwave Association (EuMA) the 11th annual European Microwave Week was organized in the Amsterdam RAI Congress Centre, The Netherlands, 27-31 October 2008. This major event consisted this year of five conferences, an exhibition, and various side events. The 38th European Microwave Conference (EuMC), the Third...journal article 2009