نتایج جستجو برای: active antenna

تعداد نتایج: 483364  

A null steering GPS antenna array is designed in this paper. In the proposed method, the exact full wave antenna radiation properties with the effect of mutual couplings and nearby scatterers are considered to calculate the array steering vector, precisely. Although the proposed method is not constrained by the array geometry and the antenna element specifications, a five patch antenna elements...

1990
L. O. Upton

One of the most important functions of a radar antenna is to provide spatial filtering that maximizes the radar's sensitivity in the desired sUIveillance direction while suppressing interference signals that enter the radar from other directions. This article describes a UHF radar antenna systemwith exceptional interference-rejection capabilities that are achieved through a combination of preci...

عسکری, غلامرضا, فیروزه, ذاکرحسین, مداح علی, محسن, نصیریان, مرضیه,

In this paper, the design and simulation of an antenna for SAR applications, with specified imaging characteristics, is proposed. The antenna should represent a wideband impedance bandwidth and also a high gain; so the design of a microstrip array antenna with proximity coupling feed and U-shaped slot patch is considered. First, the main design parameters of such an antenna element are recogniz...

Robab Kazemi Roya Heidari,

In this paper a new UWB textile slot antenna has been designed with high precision. This work aimed to makecloser steps towards real wearability by investigating the possibilities of designing wearable UWB antenna wheretextile materials are used for the substrate as well as the conducting parts of the designed antenna. The antenna iscomposed of three textile layers: the top and bottom are condu...

An axially corrugated horn antenna with an elliptically shaped taper is proposed for satellite communication applications. This structure is a good candidate for the feed of reflectors and also for improving the electrical properties of reflector antennas. A tapering method is used to justify the horizontal location of the corrugation profile which improves the electrical performance of the pre...

Journal: :IEICE Transactions 2010
Seung Hyun Cho Sang Woo Kim Woo Seok Cheong Chunwon Byun Chi-Sun Hwang Kyoung-Ik Cho Byung Seong Bae

Oxide material can make transparent devices with transparent electrodes. We developed a transparent oscillator and rectifier circuits with oxide TFTs. The source/drain and gate electrodes were made by indium thin oxide (ITO), and active layer made by transparent material of IGZO (Indium Gallium Zinc Oxide) on a glass substrate. The RC oscillator was composed of bootstrapped inverters, and 813 k...

Journal: :SIAM J. Imaging Sciences 2015
Josselin Garnier George Papanicolaou

We consider passive synthetic aperture imaging where a single moving receiver antenna records signals that are generated by distant unknown noise sources and backscattered by one or several reflectors. The reflectors can be imaged by migrating the autocorrelation functions of the received signals. We compare this passive synthetic aperture imaging with the usual, active synthetic aperture imagi...

Journal: :Plant physiology 1991
E Tyystjärvi A Koivuniemi R Kettunen E M Aro

High-light-induced decrease in photosystem II (PSII) electron transfer activity was studied in high- and low-light-grown pumpkin (Cucurbita pepo L.) plants in vivo and in vitro. The PSII light-harvesting antenna of the low-light leaves was estimated to be twice as big as that of the high-light leaves. The low-light leaves were more susceptible to photoinhibition in vivo. However, thylakoids iso...

2018

In this paper, hybrid modeling of Micro-strip antenna is presented. Broadband frequency of operation demonstrated by single geometry .for broadening the bandwidth and maximum directional gain (6.6dBi 8dBi) gap-coupled multi-resonator loaded on parasitic and active patch. The geometry of a single probe fed rectangular Micro-strip antenna incorporating a slot and gap coupled with parasitic and ac...

2004
Amir I. Zaghloul Steven Weiss Ozlem Kilic

Active antennas have been in use in communications satellites for decades. The antenna configurations include array-fed reflectors, multiple-beam lenses and direct radiating phased arrays. The active feedings of the antennas include single amplifier per radiating element and matrix power amplifiers shared between clusters of radiating elements. This paper reviews the combinations of antenna con...

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