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Enhanced Cell-Edge Performance with Transmit Power-Shaping and Multipoint, Multiflow Techniques

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ZTE communications 2011年第4期9卷 43-48页

作者： Philip Pietraski Gregg Charlton Carl Wang interdigital communications LLC. King Of PrussiaPA19406 U. S. A.

In this paper, we present a technique called ＂fuzzy cells＂ that builds on the multicarrier features of Long Term Evolution-Advanced （LTE-A） and high-speed packet access （HSPA）. Multiple carriers are aggregated to create a larger system bandwidth, and these carriers are transmitted at different powers by each sector antenna. This creates a set of cell-edge locations that differ from one frequency to the next. System-level simulations are performed to estimate individual user and average throughput for a hexagonal deployment of 3-sector base stations. For moderately high loads, a fuzzy cell deployment can improve tenth percentile （cell-edge） user throughput by 100% and can improve average throughput by about 30% compared with a reuse 1 scheme. Fuzzy ceils reduce inter-cell interference in the same way as higher-order reuse schemes and allow users to access the full system bandwidth.

关键词： LTE fractional frequency reuse multicarrier flow aggregation system simulation

Modeling Human Blockers in Millimeter Wave Radio Links

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ZTE communications 2012年第4期10卷 23-28页

作者： Jonathan S. Lu Daniel Steinbach Patrick Cabrol Philip Pietraski interdigital communications LLCMelvilleNY 11747 USA

In this paper, we investigate the loss caused by multiple humans blocking millimeter wave frequencies. We model human blockers as absorbing screens of infinite height with two knife-edges, We take a physical optics approach to computing the diffraction around the absorbing screens, This approach differs to the geometric optics approach described in much of the literature. The blocking model is validated by measuring the gain from multiple-human blocking configurations on an indoor link. The blocking gains predicted using Piazzi ＇ s numerical integration method （a physical optics method） agree well with measurements taken from approximately 2.7 dB to -50 dB. Thereofre, this model is suitable for real human blockers, The mean prediction error for the method is approximately -1.2 dB, and the standard deviation is approximately 5 dB.

关键词： 60 GHz diffraction human blocking loss human shadowing indoor environment millimeter wave propagation physical optics

Self-powered UVC detectors based on α-Ga_(2)O_(3) with enchanted speed performance

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Journal of Semiconductors 2024年第8期45卷 74-80页

作者： Aleksei Almaev Alexander Tsymbalov Bogdan Kushnarev Vladimir Nikolaev Alexei Pechnikov Mikhail Scheglov Andrei Chikiryaka Laboratory of Metal Oxide Semiconductors Research and Development Center for Advanced Technologies in MicroelectronicsNational Research Tomsk State UniversityTomsk 634050Russia Fokon llc Kaluga 248035Russia Department of Semiconductor Electronics and Physics of Semiconductors National University of Science and Technology MISISMoscow 119049Russia Perfect Crystals llc Saint Petersburg 194223Russia

Detectors were developed for detecting irradiation in the short-wavelength ultraviolet(UVC)interval using high-quality single-crystallineα-Ga_(2)O_(3) films with Pt interdigital *** films ofα-Ga_(2)O_(3) were grown on planar sapphire substrates with c-plane orientation using halide vapor phase *** spectral dependencies of the photo to dark current ratio,responsivity,external quantum efficiency and detectivity of the structures were investigated in the wavelength interval of 200−370 *** maximum of photo to dark current ratio,responsivity,external quantum efficiency,and detectivity of the structures were 1.16×10^(4) ***.,30.6 A/W,1.65×10^(4)%,and 6.95×10^(15) Hz^(0.5)·cm/W at a wavelength of 230 nm and an applied voltage of 1 *** high values of photoelectric properties were due to the internal enhancement of the photoresponse associated with strong hole ***α-Ga_(2)O_(3) film-based UVC detectors can function in self-powered operation mode due to the built-in electric field at the Pt/α-Ga_(2)O_(3) *** a wavelength of 254 nm and zero applied voltage,the structures exhibit a responsivity of 0.13 mA/W and an external quantum efficiency of 6.2×10^(−2)%.The UVC detectors based on theα-Ga_(2)O_(3) films demonstrate high-speed performance with a rise time of 18 ms in self-powered mode.

关键词： HVPE gallium oxide solar-blind ultraviolet detector self-powered mode

Tunable high-Q SAW resonator loaded on a changing capacitance

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Journal of Advanced Dielectrics 2020年第1期10卷 55-60页

作者： G.Ya.Karapetyan V.E.Kaydashev M.E.Kutepov T.A.Minasyan V.A.Kalinin V.O.Kislitsyn E.M.Kaidashev Laboratory of Nanomaterials Southern Federal University Stachki 200/1344090 Rostov-on-DonRussia Moscow Institute of Physics and Technology 9 Institutskiy per. 141701 DolgoprudnyRussia llc.STC“RUS” 199178Saint-Petersburg Maly av.V.I.54built 5

A tunable high-Q surface acoustic wave(SAW)resonator in the form of several parallel-connected interdigital transducers loaded on a varying capacitance on lithium niobate substrates was developed and *** working frequency range was 90-2450 MHz.A method of calculating such resonators,considering losses in the metal film as well as losses due to the propagation of SAWs and transformations into bulk waves is *** a design allows one to obtain a quality factor over 5000 in the frequency range 2400-2483 *** resonant frequency shifts by 600 kHz when the capacitance changes by±25%of the value of 21 pF(or 32 ppm/pF)and has an almost linear character.

关键词： Crystal growth directional crystallization defects internal stresses analytical methods