Showing papers by "Ahmed Soliman published in 2014"

Low specific absorption rate hexa-band coplanar waveguide-fed planar inverted-F antenna with independent resonant frequency control for wireless communication applications

Abstract: Compact low specific absorption rate (SAR) hexa-band planar inverted-F antenna (PIFA) with independent resonant frequency control is presented in this study. Two trapezoidal shaped slots are etched on the coplanar waveguide (CPW)-fed PIFA-radiating plate to create two independent resonant frequencies as well as the fundamental CPW-fed PIFA itself. Three coupled slots are added within the ground plane to create additional three independent resonant frequencies with slight effect on the other resonant frequencies. Multiband (dual, tri, quad, penta and hexa) band capabilities with bandwidth enhancement and acceptable SAR values are realised for different wireless communication applications. The SAR of human head is investigated by using Computer Simulation Technology (CST) 2012 Microwave Studio Hugo Voxel Model. The proposed antennas are fabricated and there is a good agreement between measured and simulated results.

Design of planar inverted F-antenna over uniplanar EBG structure for laptop MIMO applications

Abstract: A simple multiband of multiple-input-multiple-output (MIMO) antenna with low mutual coupling is proposed for laptop application. The proposed antenna consists of two planar inverted F-antenna (PIFA) elements. Each element consists of two trapezoidal shaped slots within the radiating plate and uniplanar electromagnetic band gap within the ground plane. EBG ground plane is used for obtaining lower cut off frequency, increase the gain, and larger bandwidth. The proposed uniplanar shape is easy to fabricate without the use of vias or other kinds of vertical connections. The proposed antenna is designed to cover two narrow bands namely GSM 1.8 GHz, upper WLAN 5.2 GHz and a wideband from 2.4 GHz to 4 GHz. Moreover, mutual coupling reduction by using EBG is studied, where two integrated antenna elements can operate simultaneously. Results show that the MIMO antenna has mutual coupling of less than -35 dB at 5.2 GHz, and less than -15 dB through other frequencies. The average envelope correlation coefficient is less than 0.3 over the operating frequencies. All these features enable the proposed antenna to be a good candidate for MIMO laptop applications.

Chest ultrasound versus chest computed tomography for imaging assessment before medical thoracoscopy

Abstract: The aim of this work was to assess the concordance between chest ultrasound (US) and chest computed tomography (CT) findings before medical thoracoscopy (MT) and the impact of the findings on the conduct and outcome of MT. The study was conducted prospectively on 52 patients referred for MT. All patients received chest X-ray (CXR), chest US, and chest CT before the procedure. Images were evaluated and findings were correlated with thoracoscopic findings. US findings were discordant with CT findings regarding consistency, septation, and loculation of effusion in 24/52 patients, with US detecting the findings in 24/24 patients. None of these findings was detectable on CT. US was superior to CT in detection of diaphragmatic nodules (16/52, 3/52, respectively). US findings affected MT conduct in 20/52 cases and outcome in 5/40 cases, and they were consistent with MT findings in 39/40 cases; US and CT missed septation in one case. US findings were concordant with CT findings regarding site and size of effusion and pleural masses, sizable nodules, and thickening. US missed discrete small parietal nodules in 10/52, consolidation in 2/52, mediastinal lymphadenopathy in 6/52, and mediastinal shift in 42/52 cases. CXR could identify mediastinal shift but none of other CT findings were missed by US. None of US-missed abnormalities directly altered MT management. US identifies more explicitly the imaging information relevant to MT compared with chest CT. Pre-MT imaging workup can be limited to CXR and US, reserving chest CT for cases in which US is technically unrevealing.

Reconfigurable independent multiband CPW-fed printed F-antenna for USB applications

Abstract: A low-profile compact printed pentaband inverted F-antenna (IFA) for wireless universal serial bus is presented in this article. The proposed antenna consists of four printed arms capacitive loaded IFA in one side and one parasitic ring slot with open end on the other side. The capacitive plate is added at end of each arm for size reduction. The proposed antenna is designed to operate at long term evaluation band 8, GSM 1800 MHz; Bluetooth 2.4 GHz, WI-MAX 3.5 GHz, and WLAN 5.2 GHz. PIN diodes are used to reconfigure the operating frequencies by switching ON/OFF modes. The proposed antennas are studied using high frequency structure simulator version 13. The components interaction including housing case, laptop, desk, and chair are studied. The proposed antennas with and without PIN diodes are fabricated. The results show good agreement between simulated and measured results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2237–2245, 2014