2012
Authors
Pereira, MR; Salgado, HM; Pereira, JR;
Publication
2012 INTERNATIONAL CONFERENCE ON ELECTROMAGNETICS IN ADVANCED APPLICATIONS (ICEAA)
Abstract
We propose the use of inverse scattering on the design of ultra wide band nonuniform coupled line directional couplers with a specified coupling response. The inverse scattering is performed using the layer peeling algorithm which is simple and of easy implementation as a computer routine. To validate the method a wide band directional coupler is designed and implemented. © 2012 IEEE.
2010
Authors
Pereira, MR; Salgado, HM; Pereira, JR;
Publication
Proceedings - 2010 12th International Conference on Electromagnetics in Advanced Applications, ICEAA'10
Abstract
We propose the use of inverse scattering for the design of filters, in microstrip technology, with a specified reflective group delay response. The inverse scattering is performed using the layer peeling algorithm. The method is simple and easily implemented numerically . To validate the method, filters with a reflective linear group delay were designed and implemented. The simulation and measurement results are shown to agree well the target response. ©2010 IEEE.
2009
Authors
Pereira, MR; Salgado, HM; Pereira, JR;
Publication
ICEAA: 2009 INTERNATIONAL CONFERENCE ON ELECTROMAGNETICS IN ADVANCED APPLICATIONS, VOLS 1 AND 2
Abstract
A method based on the theory of inverse scattering, more specifically the layer-peeling method, is used for the design of planar microwave electromagnetic bandgap filters in microstrip technology. The method was originally used for the design of fiber Bragg gratings. To validate the method, a 4-pole Chebyshev filter was designed and constructed. The measured results are shown to agree well with the specifications.
2007
Authors
Lima, NB; Miranda, HC; Pereira, JR; Salgado, HM;
Publication
2007 International Conference on Electromagnetics in Advanced Applications, ICEAA'07
Abstract
This paper presents the design of a low-pass microwave filter based on the EBG (Electromagnetic Bandgap) concept. The structure is composed of a microstrip line in one of the layers and two different periodic superimposed EBG structures in the ground plane. The first structure defines the characteristics of the filter in the pass-band whereas the second periodic structure is used to reduce the second harmonic spurious response. The filter exhibits a flat pass-band response and a cut-off rate better than 380 dB/octave. © 2007 IEEE.
2011
Authors
Luo, Q; Salgado, HM; Pereira, JR;
Publication
EUROCON 2011 - International Conference on Computer as a Tool - Joint with Conftele 2011
Abstract
This paper presents a printed two C-shaped monopoles antennas array for dual-band WLAN application. The two antenna elements are closely spaced at a distance of only 0.09 2.4GHz. High isolation between these two radiation elements is achieved by using the neutralization technique, which has been demonstrated as an effective way to increase the isolation for single band PIFA antennas [1, 2]. In this work, the neutralization technique has been implemented to the printed monopole antenna design. We demonstrate that by introducing two RF switches, we can not only design a compact monopole antenna array with high isolation for single band operation but also can extend this method to design a compact dual band antenna array. The proposed antenna array contains two C-shaped monopoles with a shorting line, on which two RF switches were integrated, connecting two arms of the antenna elements. Experiment results indicate that the proposed antenna array has a 10dB bandwidth that covers the required frequencies for dual-band WLAN applications (2.4/5.2GHz) with isolation higher than 15dB over both operation bands. The proposed antenna has been designed and optimized using Ansoft HFSS. © 2011 IEEE.
2012
Authors
Luo, Q; Quigley, C; Pereira, JR; Salgado, HM;
Publication
Proceedings of 6th European Conference on Antennas and Propagation, EuCAP 2012
Abstract
This study aims to design a compact two antennas array on a USB dongle for WLAN 5.8 GHz application (IEEE 802.11n). The proposed antenna adopts an Inverted-L antenna (ILA) structure, which can be easily integrated into an industry product. The two antenna elements are closely spaced and the high isolation between them is achieved by using the neutralization technique. Moreover, the impedance matching of both antennas is improved by introducing one vertical stub on the neutralizing line. In this way, both the isolation between the two antennas and the impedance matching of each antenna can be improved simultaneously. The experimental results show that this antenna has wide operation bandwidth (S11 <-10 dB) from 5.7 to more than 6 GHz with isolation always better than 10 dB. © 2012 IEEE.
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