Conference papers
http://nur.nu.edu.kz:80/handle/123456789/911
2024-03-29T13:35:50ZOn Self-Oscillating Wireless Power Transfer
http://nur.nu.edu.kz:80/handle/123456789/3126
On Self-Oscillating Wireless Power Transfer
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.
2017-11-13T00:00:00ZConjugately-Matched Uniaxial Metamaterials Make Extremely Efficient Absorbers, Emitters, and Reflectors
http://nur.nu.edu.kz:80/handle/123456789/1696
Conjugately-Matched Uniaxial Metamaterials Make Extremely Efficient Absorbers, Emitters, and Reflectors
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”.
2016-09-01T00:00:00ZA Double-Layer Metamaterial-Based Technique for Interference Mitigation and Shielding of Planar Microwave Structures
http://nur.nu.edu.kz:80/handle/123456789/1682
A Double-Layer Metamaterial-Based Technique for Interference Mitigation and Shielding of Planar Microwave Structures
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
2016-07-01T00:00:00ZThe distributed particle detectors and data acquisition modules for Extensive Air Shower measurements at "HT-KZ" experiment
http://nur.nu.edu.kz:80/handle/123456789/1160
The distributed particle detectors and data acquisition modules for Extensive Air Shower measurements at "HT-KZ" experiment
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
2015-01-01T00:00:00ZRandom Number Hardware Generator Using Geiger-Mode Avalanche Photo Detector
http://nur.nu.edu.kz:80/handle/123456789/1159
Random Number Hardware Generator Using Geiger-Mode Avalanche Photo Detector
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
2015-01-01T00:00:00Z