نتایج جستجو برای: آنتن uwb
تعداد نتایج: 5825 فیلتر نتایج به سال:
In February of 2002, the FCC approved the use of ultra-wideband (UWB) technology for commercial use. UWB has since been considered as a solution for the next generation of personal area networks (PANs) and wireless local area networks (WLANs). UWB (or impulse) radio employs short duration pulses to communicate, thereby spreading signal energy very “thinly” from DC to a few gigahertz [1]. The “u...
This document is about the “UWB co-existence analysis” to be published as an Ultrawaves deliverable D2.2. The document covers the co-existence studies between ultra wideband and other radio systems. If UWB systems will be adopted in a common use globally, or only in Europe, an inevitable consequence is that the UWB co-existence issues will have more and more significant role in the near future ...
In this paper, the impact of timing jitter in direct sequence ultra wideband (DS-UWB) system is investigated over multipath fading channel. Also, a novel hybrid direct sequence multiband UWB (DS-MBUWB) system is proposed to mitigate the impact of timing jitter. We analyze and compare the system performance for conventional DS-UWB and hybrid DS-MB-UWB with Rake receiver in the presence of timing...
با توجه به رشد سریع تکنولوژی تلفن همراه جهت افزایش تعداد متقاضیان این تکنولوژی ، لازم است که باند فرکانس این سیستم از 900 Mhz به 1800 Mhz انتقال یابد. استفاده از روش های دایورسیتی جهت بهبود کیفیت سیگنال دریافتی الزامی خواهد بود. صرفنظر از تکنیک های مختلفی دایورسیتی ، دریافت دو سیگنال مختلف توسط آنتن بخشی از این روش می باشد. استفاده از دو آنتن مجزا که در صفحه افقی در فاصله متناسب از یکدیگر قرار ...
Band-notch characteristic has been of great interest recently to overcome the electromagnetic interference of Ultra-wideband systems (UWB) with other existing ones. In this paper, we present a novel microstrip-fed antenna with band rejection property appropriate for UWB applications. Band-notch characteristic has been achieved by adding a rectangular resonant element to the ground section. A pr...
The paper presents a method of designing ultrawide band (UWB) pulse array beamformer in the case of nearfield. Firstly the principle of space-time processing of UWB pulse array is discussed. The radical beampattern transform based on spherical coordinates is employed to solve the nearfield beamforming of UWB pulse array. The frequency invariant technology is considered for the frequency depende...
On February 14, 2002, the Federal Communications Commission (FCC) of the United States adopted the First Report and Order that permitted the commercial operation of ultra wideband (UWB) technology (FCC, 2002). The FCC allocated a bandwidth of 7.5GHz, i.e. from 3.1GHz to 10.6GHz, to unlicensed use for UWB applications. Ultra Wideband is defined as any communication technology that occupies great...
ULTRA-WIDEBAND (UWB) transmission has recently received significant attention in both academia and industry for applications in wireless communications. UWB technology has many benefits, including high-data rate, availability of low-cost transceivers, low-transmit power, and low interference. It operates with emission levels that are commensurate with common digital devices such as laptops, pal...
UWB impulse radios (UWB-IR) have attracted increasing interest due to their potential to propose high user capacity with low-complexity and low-power transceivers (Win & Sholtz, 2000). It is approved by the Federal Communications Commission’s (FCC) Report in which the UWB spectral mask is released and published in February 2002. Most of these benefits initiate from the distinctive characteristi...
In this paper, the impact of chip duty factor (DF) on direct sequence (DS), time hopping (TH) and hybrid DS-TH ultra wideband (UWB) systems is investigated in realistic environments. Rake receivers are designed to perform energy capture (EC) on received UWB signals over multipath and multi-user environment in the presence of narrowband interference. It is found that by applying lower DF in the ...
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