A Novel U-Shaped Tri-Band Antenna on High Permittivity Multilayer Substrate for Wireless Communications

In this paper, a detailed study of a new proposed rectangular dielectric u-shaped tri-band antenna is presented. A meticulous study considering the high permittivity material effect is introduced and discussed. All the design procedures are performed by using CST MS software. Moreover, the modified shaped patch antenna by introducing a slot on the rectangular radiated patch, offers improved bandwidth and allows an important miniaturization in size. Note that the proposed antenna can be used for several wireless technologies, especially for the GSM, Bluetooth, Wi-Fi, WLAN, WiMAX, all bands GPS frequencies, ISM band and ultra wide band applications. Detailed design steps, parametric studies and the simulation results for the proposed antenna are investigated under specific scenarios. Finally some concluding remarks will be drawn

Miniature design of T-Shaped frequency Reconfigurable antenna for S-Band Application using Switching Technique

The article presents a miniature antenna with a simple geometry and a simple approach for reconfiguration. In order to make the T-shaped antenna frequency reconfigurable, we integrated Switches in specific positions. The location of the switches is determined following a study of the distribution of the surface currents of the suggested antenna. Indeed, we found that the insertion of switches in places where the concentrations of surface currents are high is irrelevant. In fact, to redirect current flow, the PIN diodes or RF Switch must be placed in positions where the distribution of the surface currents is of low concentration. These locations facilitate the establishment of new trajectories of the flux of current. As a result, a miniature tunable antenna dimension 20mm*20mm*1.6mm printed on FR4 substrate with 4.4 permittivity and with  0.04 loss tangent,   the antenna  can be adopted in many communication devices in view of its small size, its low manufacturing cost and performance on frequency sweep, the antenna operates in S-Band with an acceptable band and gain. The antenna is simulated and optimized using CST Microwave Studio

Study and Design of a Compact Parallel Coupled Microstrip Band-Pass Filter for a 5 GHz Unlicensed Mobile WiMAX Networks

In this paper, a compact parallel coupled microstrip band-pass filter (BPF) is used to design a wideband third order of the Tschebyshev elements for an unlicensed WiMAX technology. Some techniques based on the parametrical study are proposed to obtain the desired 10 % operating bandwidth filter response. The new filter is implemented on Arlon AR 1000 substrate having a relative permittivity of 10 and substrate thickness 1.1938 mm respectively. The results based on the transmission line theory approach and the commercial electromagnetic Agilent ADS and CST-MS simulators show a good agreement

Using cooperatives ontologies for the customization of hybrid mediator interrogation process

The explosion of information sources accessible via the Web created the need for mediation tools between users and heterogeneous information sources on the Web. However, the interface design of these mediators, with taking into account the wide variety of skills and knowledge of users, and the need for them to share their preferences, requires systems able to guide the user through the interrogation process. In this paper, we try to raise this challenge  by proposing, on one hand, the use of a cooperative ontology’s models, which adapt with the evolution of user’s profiles and the dynamic change of integrated sources, and secondly ensure sharing the knowledge between users which will facilitate analysis of information and improve the data quality research process in space  and time.  

Analysis and design of a compact ultra-wideband antenna with WLAN and X-band satellite notch

A compact design of ultra-wideband (UWB) antenna with dual band-notched characteristics based on split-ring resonators (SRR) are investigated in this paper. The wider impedance bandwidth (from 2.73 to 11.34 GHz) is obtained by using two symmetrical slits in the radiating patch and another slit in the partial ground plane. The dual band-notch rejection at WLAN and X-band downlink satellite communication system are obtained by inserting a modified U-strip on the radiating patch at 5.5 GHz and embedding a pair of rectangular SRRs on both sides of the microstrip feed line at 7.5 GHz, respectively. The proposed antenna is simulated and tested using CST MWS high frequency simulator and exhibits the advantages of compact size, simple design and each notched frequency band can be controlled independently by using the SRR geometrical parameters. Therefore, the parametric study is carried out to understand the mutual coupling between the dual band-notched elements. To validate simulation results of our design, a prototype is fabricated and good agreement is achieved between measurement and simulation. Furthermore, a radiation patterns, satisfactory gain, current distribution and VSWR result at the notched frequencies make the proposed antenna a suitable candidate for practical UWB applications

Design and Characterization of a Compact Single Layer Modified S-Shaped Tag Antenna for UHF-RFID Applications

In this paper, we report the design of a new compact single layer modified S-shaped tag antenna for UHF-RFID applications. To achieve a compact size of 51×34 mm2 for this tag antenna, the technique of using S shaped strip is applied, and by further adding a pair of equilateral triangular stubs into this structure, good impedance matching can be obtained at 915 MHz, which is the center frequency of the North-American UHF-RFID band (902 to 928 MHz). Besides exhibiting acceptable 5m read range in free space at 915 MHz, the proposed design shows a read range of about 4.5 when mounted on a metallic object (200 ×30 cm2) separated by spacer foam of thickness 1 cm. Furthermore, the proposed design shows a reasonable read ranges when it is mounted on different dielectrics with low permittivity. The proposed design has a simple configuration, low cost, acceptable read range, and can work on various background materials. &nbsp

Study, Modeling and Characterization of Dual- Band LNA Amplifiers Receivers Radio- Communication

The current design is especially suitable for use in multi-standard wireless receiver, in recent years; there has been a growing market for dual band transceivers for various wireless standards. IT is therefore the study of modeling and characterization of a dual LNA in radio communications receivers for their improvements. The LNA with constant bias circuit allows very interesting performance of the process. Dual-band Low Noise Amplifier (LNA) operates in the 3.9 GHz and 4.48 GHz frequency bands. RF circuit designs take two parallel LNAs with a single transistor ATF10136, and bandpass filter (BPF) networks are usually used match both the input and output ports at two different bands, are matched to 50Ω without external elements. A conventional source degeneration inductor is eliminated for higher signal gain while providing reasonable input impedance. The LNA using a constant-gm bias circuit achieves competitive and robust performances over process, voltage and temperature variation. Simulation results indicate a Noise Figure below 1.5dB and S21 above 11 dB in all frequency bands and also input and output return loss are below -11 dB for all desired frequency band while drawing 2.5mA current from a 5V power supply