Antenna Design for Ultra Wideband Application Using a New Multilayer Structure

Abstract — As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1–10.6GHz.This paper presents a work carried out within UL-TRAWAVES in the area of antenna design and analysis. A new multilayer microstrip antenna is introduced using Stacked Multiresonator patches. In order to achieve suitable bandwidth, the antenna size is fine for mobile applications. The antenna is designed, optimized and simulated using Ansoft designer. In addition results and conclusions are presented. DOI: 10.2529/PIERS060531145356 1

Study of Photo-Conductivity in MoS2 Thin Films Grown in Low-Temperature Aqueous Solution Bath

An experimental study over the optical response of thin MoS2 films grownby chemical bath deposition (CBD) method is presented. As two important factors, theeffect of bath temperature and growth time are considered on the photocurrentgeneration in the grown samples. The results show that increasing the growth time leadsto better optical response and higher difference between dark and photocurrent. Forhigher bath temperatures the layer loses its uniformity and the current reduces. Betterperformance of optical response is obtained for t=90min and T=70oC. We also studiedthe effect of post-annealing on the performance and quality of thin films. The I-Vmeasurements show no current flow for annealed films because of rupture of the filmstructure. Temporal response of the films to light source ON and OFF states is alsostudied and the results showed relaxation of photocurrent after about several seconds.The importance of the MoS2 thin films obtained by CBD method is low-temperatureprocess and large area of fabricated layers which can be used in many applications

Circularly-polarized and high-efficiency microstrip antenna with C-shaped stub for WLAN and WiMAX applications

In this article a novel planar triple-band microstrip monopole antenna with circular polarization and high efficiency is presented for wireless communications applications. This antenna with passbands at 2.4, 3.5, and 5.5 GHz is able to cover WLAN and WiMAX applications according to the IEEE 802.11b/g and IEEE 802.16 standards. The proposed antenna consists of a C-shaped stub to control the circular polarization and an inverted triangular patch which has two slots to achieve mentioned frequency bands. The proposed monopole antenna with dimensions 40×47×1.6 mm is implemented on the FR4 substrate and fed by a 50 Ω microstrip line. Parametric study for antenna dimensions and measurement results are presented in the article. The S-parameters of less than –10 dB, efficiency above 90% and omnidirectional radiation patterns are obtained in the proposed antenna. A brief comparison is made on the characteristics of the proposed antenna and other antennas presented in the articles and the results are presented

A small CPW-fed UWB antenna with dual band-notched charectrestics using two stepped impedance resonators

In this article, we propose a compact cpw-fed ultra-wideband (UWB) antenna with dual band-notched characteristics. The dual band-notched are achieved by using two stepped impedance resonators. The measured results show that the proposed antenna has an impedance bandwidth from 2.97 to 10.7 GHz (113%), defined by VSWR<2, with two notched bands, covering all the WiMAX (3.3-3.6 GHz), WLAN (5.2-5.8 GHz), the antenna has a small size (20 x 20 x 1.6 mm(3)), and almost stable omnidirectional radiation pattern. The proposed antenna is designed, simulated, fabricated, and tested, and the measured results are in good agreement with the simulations. (c) 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:464-467, 201

A NOVEL CPW-FED ANTENNA WITH DUAL BAND-NOTCHED CHARECTRESTICS FOR UWB APPLICATIONS

In this article, a coplanar waveguide fed (CPW-fed) ultra-wideband (UWB) antenna with dual band-notched characteristics is presented. Using two diamond-shaped stepped impedance resonators, two notched bands are obtained. The simulation and measurement results show that proposed antenna covers the frequency band between 2.85 and 11 GHz (118%), defined by VSWR<2. The proposed antenna has a total size 20 x 20 x 1.6 mm(3) and performed at the whole UWB with dual notched bands at WiMAX (3.4-3.6 GHz) and WLAN (5.15-5.85 GHz). The proposed antenna has a desirable VSWR level; radiation pattern characteristics for UWB frequency band rang. (C) 2015 Wiley Periodicals, Inc