2008/2
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Recent Submissions
- ItemTHz Wave Propagation on Strip Lines: Devices, Properties, and Applications(Společnost pro radioelektronické inženýrství, 2008-06) Kadoya, Yutaka; Onuma, Masayuki; Yanagi, Shinji; Ohkubo, Tetsuya; Sato, Naoko; Kitagawa, JiroWe report the propagation characteristics of THz pulses on micro-strip-lines and coplanar strip-lines, in which low permittivity polymer materials are used as the dielectric layer or the substrate. As a result of the low attenuation and small dispersion in the devices, the spectral width up to 3 THz can be achieved even after the 1 mm propagation. Spectroscopic characterizations of liquid or powder specimens are demonstrated using the devices. We also show a possibility of realizing a very low attenuation using a quadrupole mode in three strip coplanar lines on the polymer substrate.
- ItemFiber-Optic Vibration Sensor Based on Multimode Fiber(Společnost pro radioelektronické inženýrství, 2008-06) Lujo, Ivan; Klokoc, Pavo; Komljenovic, Tin; Bosiljevac, Marko; Sipus, ZvonimirThe purpose of this paper is to present a fiberoptic vibration sensor based on the monitoring of the mode distribution in a multimode optical fiber. Detection of vibrations and their parameters is possible through observation of the output speckle pattern from the multimode optical fiber. A working experimental model has been built in which all used components are widely available and cheap: a CCD camera (a simple web-cam), a multimode laser in visible range as a light source, a length of multimode optical fiber, and a computer for signal processing. Measurements have shown good agreement with the actual frequency of vibrations, and promising results were achieved with the amplitude measurements although they require some adaptation of the experimental model. Proposed sensor is cheap and lightweight and therefore presents an interesting alternative for monitoring large smart structures.
- ItemPatch Antenna Based on Metamaterials for a RFID Transponder(Společnost pro radioelektronické inženýrství, 2008-06) Ugarte-Munoz, Eduardo; Herraz-Martinez, Francisco Javier; Gonzalez-Posadas, Vicente; Segovia-Vargas, DanielIn this paper a self-diplexed antenna is proposed for a RFID transponder application. The development cycle is divided into two stages: antenna design and filters design. The antenna is based on a square microstrip patch filled with metamaterial structures. The inclusion of these structures allows simultaneous operation over several frequencies, which can be arbitrarily chosen. The antenna working frequencies are chosen to be 2.45 GHz (receiver) and 1.45 GHz (transmitter). In addition, the antenna is fed through two orthogonal coupled microstrip lines, what provides higher isolation between both ports. Some filters based on metamaterial particles are coupled or connected to the antenna feeding microstrip lines to avoid undesired interferences. This approach avoids using of an external filter or diplexer, providing larger size reduction and a compact self-diplexed antenna.
- ItemMIMO Capacity Estimation at 2 GHz with a Ray Model in Urban Cellular Environment(Společnost pro radioelektronické inženýrství, 2008-06) Vergerio, Sophie; Rossi, Jean-Pierre; Sabouroux, PierreMIMO technology promises a linear increase of capacity in function of the minimum antenna number at the transmitter and at the receiver. In order to test if these performances can be actually met in mobile communications, we propose here a study of MIMO (Multiple Input Multiple Output) capacity in urban cellular environment at 2 GHz with a help of an efficient ray propagation model. We have tested different types of base station antennas (vertically or ±45° polarized) and two different types of mobile. Capacity is found to significantly increase between SISO (Single Input Single Output) and MIMO systems, but less than usually expected. We show that return and coupling losses as low as 10% can also reduce significantly the capacity. On the other hand, we study the influence of the way to take into account received power level on the MIMO capacity estimation.
- ItemContactless Area Measurement (Contactless Planimeter)(Společnost pro radioelektronické inženýrství, 2008-06) Ricny, Vaclav; Stancik, PetrThe paper describes the designed hardware and software systems (so-called planimeters) for contactless measurement of areas (eventually geometric distances between two selected points) of planar projections of various objects. These systems operate on the principle of processing the video signal scanned by a digital camera (or TV camera).