Publications
150 results found
Goverdovsky V, Looney D, Kidmose P, et al., 2015, Co-Located Multimodal Sensing: A Next Generation Solution for Wearable Health, IEEE SENSORS JOURNAL, Vol: 15, Pages: 138-145, ISSN: 1530-437X
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- Citations: 15
Serb A, Redman-White W, Papavassiliou C, et al., 2015, Limitations and precision requirements for read-out of passive, linear, selectorless RRAM arrays, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 189-192, ISSN: 0271-4302
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- Citations: 4
Seimeni MA, Gkonis PK, Kaklamani DI, et al., 2014, Low-complexity Anti-Jamming Subcarrier scavenging strategies for OFDMA networks, Pages: 727-731
The goal of the study presented in this work is to evaluate the performance of OFDMA networks for different subcarrier allocation strategies. Considering no Channel State Information at the transmitter, two low-complexity subcarrier allocation strategies are employed so as to combat interference among inter-cell mobile subscribers and to judicious distribute power budget among them. In comparison to traditional allocation strategies, for 2/3/4/5 subcarriers per mobile subscriber and different permission ratios (10%, 30%, 40%), simulation results indicate that the proposed algorithms enhance the capacity (mean number of mobile subscribers) of the overall system. In some cases the capacity gain reaches 93.39%.
Gkonis PK, Seimeni MA, Kaklamani DI, et al., 2014, Interference reduction in MIMO-OFDMA cellular networks via cooperative antenna selection, Pages: 690-693
In this paper, the performance of a proposed antenna selection algorithm is evaluated that is based on cooperative interference mitigation among neighbouring base stations. This algorithm has been evaluated in MIMO-OFDMA multicellular networks, for various bit rates per mobile user and blocking probabilities via extended Monte Carlo simulations. As results indicate, for 64QAM modulation type and 3/4/5 allocated subcarriers per mobile user, the proposed antenna selection approach can provide up to 50%/36%/25% gain on the mean number of active users in the network compared to the case where antenna selection is performed having as sole criterion the maximization of Signal to Noise Ratio.
Salaoru I, Khiat A, Li Q, et al., 2014, Origin of the OFF state variability in ReRAM cells, JOURNAL OF PHYSICS D-APPLIED PHYSICS, Vol: 47, ISSN: 0022-3727
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- Citations: 21
Li Q, Khiat A, Salaoru I, et al., 2014, Memory Impedance in TiO<sub>2</sub> based Metal-Insulator-Metal Devices, SCIENTIFIC REPORTS, Vol: 4, ISSN: 2045-2322
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- Citations: 84
Berdan R, Lim C, Khiat A, et al., 2014, A Memristor SPICE Model Accounting for Volatile Characteristics of Practical ReRAM, IEEE ELECTRON DEVICE LETTERS, Vol: 35, Pages: 135-137, ISSN: 0741-3106
Gkonis PK, Asimakis NP, Seimeni MA, et al., 2014, A cooperative antenna selection algorithm for MIMO-OFDMA networks, Pages: 3238-3242
In this paper, the performance of a proposed antenna selection (AS) scheme for Multiple Input Multiple Output (MIMO) networks is evaluated, where the Orthogonal Frequency Division Multiple Access (OFDMA) physical layer protocol is employed. The proposed AS algorithm is based on the maximization of the ratio of desired user's signal power to the interference power caused to the network. Performance metrics are derived, such as the mean number of active users for various modulation types and services, after a sufficient number of Monte Carlo simulations. As results indicate, our proposed AS approach can provide significant throughput gain especially in cases of high data rates per active user. In particular, for three allocated subcarriers per MS, 16-QAM modulation type and 10% blocking probability, this strategy provides 33% gain on the mean number of active users compared to the case where interference is neglected during antenna selection.
Serb A, Berdan R, Khiat A, et al., 2014, Live demonstration: A versatile, low-cost platform for testing large ReRAM cross-bar arrays., IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 441-441, ISSN: 0271-4302
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- Citations: 10
Serb A, Berdan R, Khiat A, et al., 2014, Memristors as synapse emulators in the context of event-based computation, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 2085-2088, ISSN: 0271-4302
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- Citations: 1
Wizenberg R, Khiat A, Berdan R, et al., 2014, Applications of Solid-State Memristors in Tunable Filters, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 2269-2272, ISSN: 0271-4302
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- Citations: 4
Berdan R, Khiat A, Papavassiliou C, et al., 2014, Qualitative SPICE modeling accounting for volatile dynamics of TiO<sub>2</sub> memristors, IEEE International Symposium on Circuits and Systems (ISCAS), Publisher: IEEE, Pages: 2033-2036, ISSN: 0271-4302
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- Citations: 1
Chen W, Papavassiliou C, 2013, Asynchronous sigma-delta modulator with noise shaping, ELECTRONICS LETTERS, Vol: 49, Pages: 1520-1521, ISSN: 0013-5194
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- Citations: 1
Chen W, Papavassiliou C, 2013, A Low Power 10-bit Time-to-Digital Converter Utilizing Vernier Delay Lines, UKSim-AMSS 15th International Conference on Computer Modelling and Simulation (UKSim), Publisher: IEEE, Pages: 774-779
Goverdovsky V, Yates D, Papavassiliou C, 2013, Ultra-low power transmitter trade-offs for super-resolution tracking of rodents, IEEE Topical Conference on Wireless Sensors and Sensor Networks (WiSNet), Publisher: IEEE, Pages: 37-39, ISSN: 2330-7900
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- Citations: 2
Chen W, Papavassiliou C, 2013, A New Decoding Solution for the Asynchronous Sigma Delta Modulator, 9th Conference on Ph D Research in Microelectronics and Electronics (PRIME), Publisher: IEEE, Pages: 49-52
Prodromakis T, Peh BP, Papavassiliou C, et al., 2011, A Versatile Memristor Model With Non-linear Dopant Kinetics, IEEE Transactions on Electron Devices, Vol: 58, Pages: 3099-3105, ISSN: 0018-9383
Prodromakis T, Konstantinidis G, Papavassiliou C, et al., 2010, Interfacial polarisation on gallium arsenide membranes, Micro & Nano Letters, IET, Vol: 5, Pages: 178-180, ISSN: 1750-0443
An investigation on the dielectric properties of gallium arsenide membranes is presented. Particularly, the authors exploit the interfacial polarisation effect of microstrip and coplanar transmission lines on multilayered membrane structures. Such structures are in favour with the Maxwell-Wagner polarisation, which can be used for resembling the dielectric characteristics of high-k materials. The authors demonstrate a technique for attaining large slowing factors while the corresponding dielectric losses are significantly reduced.
Prodromakis T, Papavassiliou C, 2010, An Experimental Technique for Characterizing Slow-Wave Characteristics of MIS-Like Transmission Lines Using Aqueous Dielectrics, Transactions on Microwave Theory and Techniques, Vol: 58, Pages: 985-993
This work is a study of the dielectric propagation properties of laminar substrates, which are known to support low dispersion modes with very small phase velocities. Slow modes are linked to a polarization mode supported by the insulator–semiconductor interface. The mode spectrum of metal–insulator–semiconductor lines is controlled by the substrate resistivity and the ratio of the semiconductor to insulator layer thicknesses. An experimental investigation of substrate modes normally requires the laborious fabrication of many specimens to cover a useful range of parameter variation. In this paper, we present an experimental platform that supports slow-wave propagation and allows easy adjustment of the parameters affecting the interfacacial polarization mechanism.
Pu SH, Holmes AS, Yeatman EM, et al., 2010, Stable zipping RF MEMS varactors, JOURNAL OF MICROMECHANICS AND MICROENGINEERING, Vol: 20, ISSN: 0960-1317
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- Citations: 13
Kiziroglou ME, Mukherjee AG, Vatti S, et al., 2010, Self-assembly of three-dimensional Au inductors on silicon, IET microwaves, antennas & propagation, Vol: 4, Pages: 1698-1703, ISSN: 1751-8733
Prodromakis T, Papavassiliou C, Toumazou C, 2010, Application of Maxwell-Wagner Polarization in Delay Lines, Microelectronics Journal, Vol: 41, Pages: 17-24
The propagation characteristics of metal–insulator–semiconductor (MIS) lines are controlled by the resistivity of the substrate, the operating frequency and the ratio of the semiconductor to insulator layer thicknesses. A strong interfacial polarisation, also known as the Maxwell–Wagner polarisation, is often responsible for the significant slow-down of the propagation velocity of MIS microstrip transmission lines. This phenomenon has been applied in the development of miniature delay lines exhibiting large electrical dimensions. In this paper we review most previously presented designs and we examine the effect of this polarization mechanism under various parameters. Finally, the presented micro-scale delay lines, exhibit comparable slowing factors with our predecessors at the cost of lower attenuation.
Tuckwell M, Papavassiliou C, 2009, An Analog Gabor Transform Using Sub-Threshold 180-nm CMOS Devices, Circuits and Systems I: Regular Papers, IEEE Transactions on, Vol: 56, Pages: 2597-2608, ISSN: 1549-8328
The Gabor transform can be used to represent a signal in terms of a set of pseudo basis functions, allowing a signal to be split into parallel paths of a lower bandwidth. An analog Gabor transform using sub-threshold CMOS continuous time filters designed from time domain impulse responses is described. A novel method for designing low power gm-C filters using simple models of identical transconductors is used to specify the transistor sizes. Measured results show that the transform consumes 7 ??W for an input signal bandwidth of 4 kHz, making it suitable for ultra low power systems.
Prodromakis T, Papavassiliou C, Konstantinidis G, et al., 2009, Application of gold nanodots for Maxwell-Wagner loss reduction, MICRO NANO LETT, Vol: 4, Pages: 80-83, ISSN: 1750-0443
Any element or mechanism that can cause a spatial variation of charge density can contribute to the dielectric susceptibility of a structure. Particularly, we focus on metal-insulator-semiconductor (MIS) structures that support interfacial polarisation. Since energy storage and dissipation are two aspects of the same phenomenon, the attainable large effective electric permittivity of such structures is accompanied by comparably large dielectric losses that prohibit practical application in monolithic-microwave integrated circuits (MMICs). The authors present a process technique for developing gold nanodots buried in the insulating medium that con. ne the electric field within the oxide layer, that is prohibiting E-field penetration to the substrate, which is rather lossy. Measured results demonstrate that the proposed structure exhibits an almost identical effective electric permittivity with a standard MIS, nonetheless the losses are decreased.
Prodromakis T, Papavassiliou C, 2009, Engineering the Maxwell-Wagner polarization effect, Applied Surface Science, Vol: 255, Pages: 6989-6994
Layered structures, when supporting the Maxwell–Wagner polarization mechanism, exhibit very large effective electric permittivity and thus can be used for miniaturizing purposes. However, the large interfacial dimensions evolved, limit the Maxwell–Wagner polarization at relatively low frequencies. Any element or mechanism that causes a spatial variation of charge density, contributes to the dielectric susceptibility of a medium. Thus, intentionally planted polarization states can be used for further exploiting the Maxwell–Wagner polarization mechanism.
Prodromakis T, Papavassiliou C, 2009, Surface texturing for Maxwell–Wagner polarisation engineering, Micro & Nano Letters, Vol: 4, Pages: 5-8
This letter describes surface texturing techniques that are applied in laminar structures for extending the supported Maxwell-Wagner polarization. The roughness of the semiconductor surface is increased, resulting in a subdivision of the large Si-SiO2 interfaces to a multitude of small interfaces. Measured results demonstrate that these surface texturing has a direct effect on the Maxwell-Wagner polarization relaxation and in particular at the interfacial to atomic polarization transition.
Mukherjee AG, Vatti S, Kiziroglou ME, et al., 2009, Integration of self-assembled inductors with CMOS LC oscillators, Microwave Conference, 2009. EuMC 2009. European, Pages: 1876-1879
The quality factor (Q) of integrated inductors is of great importance to radio frequency applications. Monolithic integration of out-of-plane Au inductors with Complementary Metal-Oxide-Semiconductor (CMOS) LC oscillators is reported in this paper. The recently developed self-assembly process involves in-plane fabrication of Au inductors and subsequent rotation of the structure by surface tension forces of a melting Sn hinge. The CMOS compatibility of this process is demonstrated through the integration of an LC oscillator with the self-assembled inductor using post-CMOS processing. At a 1.48 GHz oscillation frequency, a phase noise of -95 dBc/Hz is reported at a 100 kHz frequency offset. Obtained results show this technique to be promising for the integration of high Q inductors with commercial RF systems.
Mukherjee AG, Vatti S, Kiziroglou ME, et al., 2009, Integration of self-assembled inductors with CMOS LC oscillators, Microwave Integrated Circuits Conference, 2009. EuMIC 2009. European, Publisher: IEEE, Pages: 523-526
Prodromakis T, Papavassiliou C, Michelakis K, 2008, A Ka-band true-delay-line phase shifter using capacitive MEMS switches, MEMSWAVE
Prodromakis T, Papavassiliou C, Michelakis K, 2008, Microstrip Stepped Impedance LowPass Filters based on the Maxwell-Wagner Polarization Mechanism, IEEE International Symposium on Circuits and Systems, Pages: 616-619
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