Antennas Array
Mostrando 1-12 de 34 artigos, teses e dissertações.
-
1. C-Band Monopulse Planar Array and Feeding Network
Abstract Monopulse radars operate with simultaneous beams and are used for tracking purposes, relying only on hardware to provide a real-time indication of the target position. A monopulse array and its feeding network is implemented and tested, in the frequency of 5.4 GHz, based on patch antennas using dieletric to provide wide bandwidth and high gain. The
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
-
2. Omni-Directional Wideband Antenna Array with Solar Cells
Abstract Distributed sensor networks are becoming more and more widespread due to their substantial benefits to our daily lives. These sensors, in most cases, are distributed in nature and even may require mobility. This, in turn, implies omnidirectional collector units to collect the data from various sensors at arbitrary directions. This work summarizes th
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
-
3. Double Patch Antenna Array for Communication and Out-of-band RF Energy Harvesting
Abstract This paper presents a patch antenna array topology for Simultaneous Wireless Information and Power Transfer (SWIPT) applications. The resulting Double Patch Antenna Array (DPA) is composed of two patch antennas operating at different frequencies and fabricated on a unique substrate. One of the patches operates at the 1.8 GHz mobile communication ban
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
-
4. Mutual Coupling Reduction in Phased Array Antennas Applying High-Impedance Surface at X Band
Abstract This paper presents a microstrip phased array using High Impedance Surface - Electromagnetic Bandgap (HIS-EBG) in order to minimize the effects of mutual coupling among the antenna elements. Each element of the array is fed by a coaxial cable allowing the beam steering by controlling the signal of the input port of each element. This phased array op
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-03
-
5. Optimization of Planar Antenna Arrays Using the Firefly Algorithm
Abstract This paper describes the application of the Firefly Algorithm for the optimization of linear and planar antenna arrays. In order to demonstrate the potential of this technique, three applications are reported. The first one is the synthesis of a radiation pattern with isoflux distribution with a non-uniformly spaced linear array composed of isotropi
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2019-03
-
6. Polarization Insensitive Compact Wide Stop-band Frequency Selective Surface
Abstract A compact, polarization insensitive, wide stop band frequency selective surface is presented. The unit cell is designed by modifying the basic square loop FSS. The simulated value of bandwidth for transmission < ‒ 20 dB for TE incident wave is 7.7 GHz from 4.71 GHz to 12.41 GHz which is 89.95% corresponding to the center frequency of this range. I
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2018-03
-
7. Quantum Particle Swarm Optimization for Synthesis of Non-uniformly Spaced Linear Arrays with Broadband Frequency Invariant Pattern
Abstract This paper describes a method using Quantum Particle Swarm Optimization to obtain a broadband frequency invariant pattern for synthesis of nonuniformly spaced linear array of isotropic antennas. Two cases related to this work using QPSO have been studied, namely, in the first case, the generated frequency invariant far-field pattern is broadside in
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-09
-
8. ANALYTICAL METHOD FOR DESIGNING FSS-BACKED REFLECTARRAY ANTENNA USING TRANSMISSION LINE APPROACH
Abstract The main purpose of this paper is introducing a new method based on the transmission line approach for designing FSS-backed reflecarray antennas. For this reason a dual band reflectarray antenna is designed. This antenna contains a conventional single layer RA and a FSS backed double layer RA with 54% and 50% efficiency operating at X band and K ban
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
-
9. Polarization Diversity on ESM Systems
Abstract Polarization diversity antenna arrays are applied to electronic support measures (ESM) systems since the 1980s. However, even today modern systems are conceived with the employment of the traditional and inconvenient spiral antennas and there are no studies that evidences most of the benefits of this technique applied to them. This paper aims at sho
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
-
10. Dynamic analysis of superconductor at high temperature for antennas array
The analysis and new results of the resonance frequency and radiation pattern of antennas array, for glass fiber FR-4 substrate using superconductor and copper patch, are presented. The linear superconducting rectangular antennas array uses the new materials SnBaCaCuOy at temperature of 160 K with conductivity equal 1.5 x 10(5) S/m. The concise full wave Tra
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
-
11. A CMOS UWB transmitter with Vivaldi Array for Ultra-fast Beam steering microwave radar
This work presents a new Ultra Wide Band (UWB) beamforming fifth-order derivative Gaussian pulse transmitter with dual small Vivaldi antennas for remote acquisition of vital signals in impulse radar applications. The system consists of a programmable delay circuit (PDC or τ), a UWB pulse generator (PG) circuit and an array of two Vivaldi planar antennas. Th
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
-
12. Sobre modelos e métodos de estimação de direção de chegada de sinais em sistemas digitais de comunicação sem fio / On models and methods for direction of arrival estimation of signals in digital wireless communication systems
This thesis deals with the problem of estimating the direction of arrival of digitally modulated signals, specifically found in the uplink of multiuser wireless communication systems where the base station uses an antenna array. The main objectives of the thesis are: to clarify some details normally not treated in the description of the data models assumed i
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/08/2011