Conference papers

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    A Double-Layer Metamaterial-Based Technique for Interference Mitigation and Shielding of Planar Microwave Structures
    (2016-07) Papadimopoulos, Athanasios; Karamanos, Theodosios; Tsitsas, Nikolaos; Valagiannopoulos, Constantinos; Kantartzis, Nikolaos; Tsiboukis, Theodoros
    An efficient cloaking-shielding technique based on the use of a double superstrate-layer overlay is developed in this paper for planar microstrips. The metamaterial-inspired formulation reduces considerably the induced on the strip current and the reflected from the microstrip electric field, thus alleviating the electromagnetic susceptibility of microstrip transmission lines. For this purpose, the mathematical analysis and optimization procedure are founded on a semianalytic integral equation algorithm, while a set of numerical results certifies its promising merits
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    Conjugately-Matched Uniaxial Metamaterials Make Extremely Efficient Absorbers, Emitters, and Reflectors
    (2016-09) Valagiannopoulos, Constantinos; Simovski, C. R.; Tretyakov, Sergei A.
    The speed with which electromagnetic energy can be wirelessly transferred from a source to the user is a crucial parameter for performance of a large number of electronic and photonic devices. In this presentation we determine the constituent parameters of a medium which supports theoretically infinite energy concentration close to a medium sample surface; such a material combines properties of Perfectly Matched Layers (PML) and Double-Negative (DNG) media. It realizes conjugate matching with free space for every possible mode including, most importantly, all evanescent modes. We show that extremely high-amplitude resonating fields in the vicinity of a conjugately matched body can create large far-field radiation with the use of randomly placed particles which play the role of emission “vessels”.
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    On Self-Oscillating Wireless Power Transfer
    (IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS), 2017-11-13) Tretyakov, Sergei; Ra’di, Younes; Simovski, Constantin; Valagiannopoulos, Constantinos
    Abstract—Conventional wireless power transfer systems consist of a microwave power generator located at one place and a microwave power receiver located at a distance. To realize efficient power transfer, the system brought to resonance and the coupled-antenna mode is optimized to reduce radiation into surrounding space. In this scheme, moving or varying a receiver results in a necessity of the difficult tuning the whole systems that implies a complex and energy consuming feed-back structure. We propose a new paradigm of wireless power delivery where the whole system, including transmitter and receiver, is a united microwave power generator. Instead of first converting DC or 50/60 Hz power into microwaves and then arranging a wireless transfer link between two antennas, in our proposed scenario microwave oscillations are directly generated at the receiver location, eliminating the need for dynamical tuning of the system impedances.
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    Random Number Hardware Generator Using Geiger-Mode Avalanche Photo Detector
    (2015) Beznosko, Dmitriy; Beremkulov, T.; Duspayev, A.; Iakovlev, A.
    The main problems with existing hardware random number generators today are either low speed and/or prohibitively high cost. The physical concept and test results of sample data of the high-speed hardware true random number generator design based Hamamatsu MPPC photo sensor are shown. Main features of this concept are the high speed of the true random numbers generation (tens of Mbt/s), miniature size and estimated lower production cost. This allows the use of such a device not only in large companies and government offices but for the end-user data cryptography, in classrooms, in scientific Monte-Carlo simulations, computer games and any other place where large number of true random numbers is required. The physics of the operations principle of using a Geiger-mode avalanche photo detector is briefly discussed and the high quality of the data collected is demonstrated
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    The distributed particle detectors and data acquisition modules for Extensive Air Shower measurements at "HT-KZ" experiment
    (2015) Duspayev, A.; Batyrkhanov, A.; Beremkulov, T.; Beznosko, Dmitriy; Iakovlev, A.; Yessenov, M.; Beisembaev, R. U.; Zhukov, V. V.
    "HorizonT-Kazakhstan" (HT-KZ) is an extensive air shower new detector system of a new type to be constructed at Nazarbayev University (NU), Astana, KZ. It is based on the idea of a previous generation detector that is located at Tyan-Shan high-altitude Science Station of the Physical Institute of Russian science academy at approximately 3340 meters above the sea level. It will consist of 8 independent modules distributed on the roofs of NU with 1-2ns time resolution. The purpose is to register Extensive Air Showers (EAS) coming from a wide range of zenith angles. The measurements of the time characteristics of the EAS are to be taken simultaneously at up to eight registration points separated by the distance up to one kilometer. HT-KZ development is very important step in the EAS research area, especially, in the presence of the last connected discoveries, such as multi-modal events This article presents the current system development state, the R&D work of the system modules using the independent particle detection modules. The distributed DAQ system and event synchronization system progress will be discussed as well