Design of planar inverted-F antennas (PIFA) for multiband wireless applications

A small three bands printed inverted-F antenna with independently controlling the resonant frequency is presented. The proposed antenna consists of two arms supported by shorting walls fed by 50 Ω microstrip transmission line and a ground plane. The antenna occupied a compact size of 26 x 25 x 3.75 mm. The main radiated patch injected with slot and another arm to generate and control the three resonant frequencies to cover 2.4, 3.7 and 5.2GHz Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX). The simulated and measured results show that the antenna achieves a gain of 2, 3 and 5 dBi respectively and radiation efficiency of 50%, 60% and 85% for the three bands respectively. The simulated and measured result for the return loss is in good agreements

Double U-slots patch antenna for tri-band wireless systems

File shown is the pre-print version of the published paper, with the title "Connected u-slots pathch antenna for WiMAX applications"ABSTRACT: A compact microstrip patch antenna with two U-slots shape is presented. Detailed simulation and experimental investigation are conducted to understand the behavior of the two U-slots. The proposed antenna generates three resonant frequencies at 2.7, 3.3, and 5.3 GHz. It can, therefore, be used in Worldwide Interoperability for Microwave Access compliant communication equipment. The proposed antenna has two U-slot shaped and two bridge elements to connect both shapes together to adapt the structure to the desired interest operating frequency. A comprehensive parametric study has been applied to understand the effect of each U-slot on the antenna’s performance. Moreover, the current distribution for the three bands is investigated to give further understanding of the antenna behavior. The proposed antenna is verified experimentally and the simulated and measured results are in good agreement

Reconfigurable wideband patch antenna for cognitive radio

Cognitive radio communication is envisaged to be a new paradigm of methodologies for enhancing the performance of radio communication systems through the efficient utilization of radio spectrum. A key enabler for realization of a cognitive communication system is the capability of re-configurability in the underlying hardware and the associated protocol suite. Reconfigurable double C-Slot microstrip patch antenna fed by 50 ohm microstrip line is proposed in this paper. The frequency tuning is performed by switching on and off two patches. The antenna can operate in dual-band or in very wide band mode in 5, 6 and 7 GHz bands. The wide-band mode can be obtained when both switches are in the ON state with impedance bandwidth of 33.52 % from 4.99 to 7 GHz. The total size of the ground plane is 50 x 50 mm2. The proposed antenna verified through both numerical simulation and measurement of an experimental prototype. The antenna achieves a gain of 5 to 8 dBi and radiation efficiency about 80%

MRAI Optimization for BGP Convergence Time Reduction without Increasing the Number of Advertisement Messages

AbstractThe primary cause for the slowness of the Border Gateway Protocol (BGP) convergence delay is the Minimum Route Advertisement Interval (MRAI). The MRAI is a timer with a default value of 30seconds, which forces the BGP routers to wait for at least that amount of time before sending an advertisement for the same prefix. This process can delay important BGP advertisements. To date, there has been no specific value used by all the networks around the Internet. This paper aims to find the optimum value for the MRAI timer that maximally reduces the convergence time without increasing the number of advertisement messages. The optimal MRAI value founded by this paper reduced the convergence time by minimum 45%

A reconfigurable wideband and multiband antenna using dual-patch elements for compact wireless devices

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 IEEEA reconfigurable wideband and multiband C-Slot patch antenna with dual-patch elements is proposed and studied. It occupies a compact volume of 50 × 50 × 1.57 (3925 mm3), including the ground plane. The antenna can operate in two dual-band modes and a wideband mode from 5 to 7 GHz. Two parallel C-Slots on the patch elements are employed to perturb the surface current paths for excitation of the dual-band and the wideband modes. Two switches, implemented using PIN diodes, are placed on the connecting lines of a simple feed network to the patch elements. Dual-band modes are achieved by switching “ON” either one of the two patch elements, while the wideband mode with an impedance bandwidth of 33.52% is obtained by switching “ON” both patch elements. The frequencies in the dual-band modes can be independently controlled using positions and dimensions of the C-Slots without affecting the wideband mode. The advantage of the proposed antenna is that two dual-band operations and one wideband operation can be achieved using the same dimensions. This overcomes the need for increasing the surface area normally incurred when designing wideband patch antennas. Simulation results are validated experimentally through prototypes. The measured radiation patterns and peak gains show stable responses and are in good agreements. Coupling between the two patch elements plays a major role for achieving the wide bandwidth and the effects of mutual coupling between the patch elements are also studied

On the Energy Efficiency of Virtual Machines’ Live Migration in Future Cloud Mobile Broadband Networks

In this chapter, a live migration of the virtual machine (VM) power consumption (PC) model is introduced. The model proposed an easy and parameterised method to evaluate the power cost of migrating the VMs from one server to another. This work is different from other research works found in the literature. It is not based on software, utilisation ratio or heuristic algorithms. Rather, it is based on converting and generalising the concepts of live migration process and experimental results from other works, which are based on the aforementioned tools. The resulting model eventually converts the power cost of live migration from a function of utilisation ratio to a function of server PC. This means there will be neither a need for additional hardware, a separate software, nor a heuristics-based algorithms to measure the utilisation. The resulting model is simple, on the fly and accurate PC evaluation. Furthermore, the latency cost of live migration process, included the time it take the VM to be completely transferred to the target server, alongside the link distance/delay between the two servers is discussed

Wide-band planar inverted-F antenna for cognitive radio

A wide-band planar inverted-F antenna (PIFA) is presented. The proposed antenna is simply structured consist of main patch supported by shorting wall and shorting pin, fed by 50 ohm microstrip transmission line. The antenna achieves an enhanced impedance bandwidth of 64.5 % covering from 2.1 to 4.1GHz with a stable radiation performance in terms of gain from 6-8 dBi. The radiated patch occupied a total volume of 53 × 55 mm. The antenna was studied by means of numerical simulation; the achieved -10 dB bandwidth of the antenna is confirmed and demonstrated by experimental measurements. The simulated and measured results are in good agreements

Compact planar inverted-F antenna (PIFA) for WiMAX application

This paper has focused on the development of multi-band planer inverted-F antenna for use in the three bands WiMAX application. Four slots have been added on the radiated patch to give the required three bands for the WiMAX 2.6, 3.6 and 5.6 GHz, the effect of each slot has been discussed. Both simulated and measured results have been presented

A reconfigurable H-shape antenna for wireless applications

This paper presents a novel H-Shaped reconfigurable microstrip patch antenna fed by a Grounded Coplanar Waveguide (GCPW) for wireless applications. The uniqueness in the presented antenna design relies in the ability to select the number of operating frequencies electronically by using a varactor diode. The antenna structure consists of coplanar waveguide (CPW) input with an H-shape printed on a PCB and a varactor diode for reconfigurability. By electronically varying the value of the diode capacitance, the antenna can operate in a single band mode to cover Global Position System (GPS), a dual band mode to cover GPS and Global System for Mobile communications (GSM1900) or a three-band mode to cover GPS, GSM1900 and Bluetooth or Wireless Local Area Networks (WLAN)