نتایج جستجو برای: آنتن uwb
تعداد نتایج: 5825 فیلتر نتایج به سال:
Ultra Wide Bandwidth (UWB) techniques are getting an increased importance due to their many features such as high bit rates availability, low power consumption and location capabilities. UWB technology enables the development of advanced wireless local area networks providing integrated multimedia services to nomadic users over hot-spot areas. The assessment of the possible interference caused ...
در اکثر سیستم های تله متری فضایی از حداقل دو آنتن فرستنده برای ارسال سیگنال رادیویی به سمت آنتن گیرنده استفاده می شود. دلیل آن تأثیر بدنه بزرگ و فلزی اجسام پرنده در قطع ارتباط رادیویی بین آنتن فرستنده و آنتن گیرنده در حین مانورهای پروازی است. نصب دو آنتن فرستنده برروی بدنه جسم پرنده ارتباط مناسب و دائم رادیویی بین فرستنده و گیرنده تله متری را تضمین خواهد کرد، ولی در لحظاتی از پرواز که آنتن گیرن...
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 ...
A novel transceiver design for ultra wideband (UWB) communication systems using the channel phase precoding (CPP) technique is proposed in this work. With the CPP-UWB transceiver, we encode data symbols using the reversed order of the channel phase. A simple phase estimation algorithm is presented for the CPP-UWB implementation. Owing to its ability to coherently combine the channel magnitude o...
A uniformly spaced comb taper slot antenna array is proposed for directional ultra-wideband (UWB) applications. The UWB array consists of four identical comb taper slot antennas, a mutistage with four-way microstrip UWB power divider, and four identical coaxial cable lines. A maximum gain of 15.5dBi within the band is obtained when the element separation is properly selected. The uniform spacin...
This paper describes a novel approach for 3D localization of an object based on fusion of the UWB radio localization techniques and UWB Impulse Radar ranging possibilities. We present a 3D localization system which includes five base stations and a TAG, and introduce the principles of our localization method. The simulation and experimental results indicate that the UWB technology based localiz...
Recently, an ultra wideband (UWB) impulse radio draws much attention due to its potential low cost and low power consumption properties. The Federal Communications Commission (FCC) is currently working on setting emission limits that would allow UWB communication systems to be deployed on an unlicensed band following the Part 15 rules for radiated emissions of intentional radiators [1]. The UWB...
A novel compact UWB antenna with 3.5/5.5 GHz dual notch-band characteristics is presented. The proposed antenna has a simple structure and compact size of 30 × 35mm2. Firstly, a compact modified rotated monopole antenna that covers UWB band is achieved. Then by inserting a λ/4 stub and etching two symmetrical λ/4 L-shape slots on the UWB antenna achieved before, a dual band-notched ultra-wideba...
In this paper, we propose a direct sequence ultra wideband (DS-UWB) radar system using a short-length pseudo noise (PN) sequence. The proposed DS-UWB radar reduces the correlation processing time by averaging out the noise in the correlator outputs, and thus, employs a short-length PN sequence unlike the conventional DS-UWB radar systems using multiple variable-length PN sequences. Numerical re...
In this paper, the effects of Bragg scattering on ultrawideband (UWB) signal transmission from periodic surfaces are reported. First, the frequency dispersive property of Bragg scattering is theoretically and experimentally confirmed. Next, the transfer function of both specular path and Bragg scattering are extracted. Then direct sequence UWB (DS-UWB) transmission simulations are conducted by ...
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