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Search Results: 1 - 10 of 6614 matches for " Philip Abbosh "
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Design of a CPW-Fed Band-Notched UWB Antenna Using a Feeder-Embedded Slotline Resonator
Amin M. Abbosh
International Journal of Antennas and Propagation , 2008, DOI: 10.1155/2008/564317
Abstract: A complete design method for a compact uniplanar ultra-wideband antenna with subband rejection capability is presented. A slotline resonator is incorporated in the coplanar waveguide feeder of the antenna to act as a bandstop filter, hence enabling the rejection of any undesired band within the passband of the antenna. Two samples of the proposed antenna were designed and manufactured. One of the developed antennas does not contain a resonator, whereas the other contains a slotline resonator. The designed antennas feature a compact size of 27 mm × 27 mm. Results of the simulation and measurement show that the designed antennas have a bandwidth from 3 GHz to more than 11 GHz. The results also reveal that the use of the resonator in the feeder of the antenna efficiently rejects any undesired subband, such as the 4.9–5.9 GHz band assigned for IEEE802.11a and HIPERLAN/2. The gain of the antennas with the resonator is about 2.2 dBi at the passband, while it is less than −8 dBi at the rejected subband.
Directive Antenna for Ultrawideband Medical Imaging Systems
Amin M. Abbosh
International Journal of Antennas and Propagation , 2008, DOI: 10.1155/2008/854012
Abstract: A compact and directive ultrawideband antenna is presented in this paper. The antenna is in the form of an antipodal tapered slot with resistive layers to improve its directivity and to reduce its backward radiation. The antenna operates over the frequency band from 3.1 GHz to more than 10.6 GHz. It features a directive radiation with a peak gain which is between 4 dBi and 11 dBi in the specified band. The time domain performance of the antenna shows negligible distortion. This makes it suitable for the imaging systems which require a very short pulse for transmission/reception. The effect of the multilayer human body on the performance of the antenna is also studied. The breast model is used for this purpose. It is shown that the antenna has more than 90% fidelity factor when it works in free space, whereas the fidelity factor decreases as the signal propagates inside the human body. However, even inside the human body, the fidelity factor is still larger than 70% revealing the possibility of using the proposed antenna in biomedical imaging systems.
Design of Dual-Band Microstrip Reflectarray Using Single Layer Multiresonance Double Cross Elements
Amin M. Abbosh
PIER Letters , 2010, DOI: 10.2528/PIERL09111612
Abstract: A multiresonance double cross element is used to design a dual-band reflectarray with dual linear polarization. The proposed element has a single conductive layer structure which makes it easy to manufacture. The results presented in this paper show that the mutual effect between the elements of the two bands is negligible. Hence, it is easy to achieve the phase compensation for each band separately. The simulated and measured results for an element designed to cover the X- and K-bands have confirmed the suitability of the proposed element to build a dual-band reflectarray.
Metabotropic glutamate receptor 5 (mGluR5) regulates bladder nociception
Lara W Crock, Kristina M Stemler, David G Song, Philip Abbosh, Sherri K Vogt, Chang-Shen Qiu, H Henry Lai, Indira U Mysorekar, Robert W Gereau IV
Molecular Pain , 2012, DOI: 10.1186/1744-8069-8-20
Abstract: Using a combination of genetic and pharmacologic approaches, we provide evidence indicating that mGluR5 is necessary for the full expression of VMR in response to bladder distention in the absence of inflammation. Furthermore, we observed that mice infected with a uropathogenic strain of Escherichia coli (UPEC) develop inflammatory hyperalgesia to bladder distention, and that the selective mGluR5 antagonist fenobam [N-(3-chlorophenyl)-N'-(4,5-dihydro-1-methyl-4-oxo-1H-imidazole-2-yl) urea], reduces the VMR to bladder distention in UPEC-infected mice.Taken together, these data suggest that mGluR5 modulates both inflammatory and non-inflammatory bladder nociception, and highlight the therapeutic potential for mGluR5 antagonists in the alleviation of bladder pain.Interstitial cystitis/painful bladder syndrome (IC/PBS) is a serious and painful condition of unknown etiology that affects 3-6% of women in the United States [1,2]. The major clinical symptom of IC/PBS is pain upon bladder filling (distention) leading to urinary frequency and urinary urgency [3]. The current available treatments are often ineffective and do not treat the underlying pathology. Rodent bladder-injury models that induce some of the symptoms observed in IC/PBS have been used to evaluate potential treatments for IC/PBS [4-9]. One injury model, bacterial cystitis (urinary tract infection, UTI) is known to cause a similar constellation of symptoms as observed in IC/PBS (i.e. urinary frequency and urgency [10-12]). In addition, bacterial cystitis can be modeled in rodents through bladder exposure to uropathogenic Escherichia Coli (UPEC) [13,14]. Bladder infections due to UPEC are responsible for approximately 80% of UTIs in otherwise healthy women [15,16]. Understanding the underlying molecular mechanisms of both non-inflammatory bladder pain and inflammatory bladder pain due to UPEC infection could lead to the development of novel treatments for painful bladder infections as well as for IC/PBS and po
Compact Planar Microstrip Crossover for Beamforming Networks
Bassem Henin;Amin M. Abbosh
PIER C , 2012, DOI: 10.2528/PIERC12081515
Abstract: The design of a fully planar microstrip crossover for beamforming networks is presented. The design starts by using a conventional half-wavelength square patch and two sets of orthogonal feeding lines. Rectangular and circular slots are introduced on the square patch in order to reduce the required area of the patch by 82%. The proposed crossover is fabricated and tested for performance confirmation. The measured data shows less than 1 dB insertion loss, more than 13 dB isolation, and around 0.1 ns deviation in the group delay across 12% fractional bandwidth. The proposed crossover is suitable for planar Butler matrix which is a key component in beamforming networks.
Utilizing Symmetry of Planar Ultra-Wideband Antennas for Size Reduction and Enhanced Performance
Ahmed Toaha Mobashsher,Amin Abbosh
Physics , 2015,
Abstract: With the increasingly new ultra wide-band applications, antenna researchers face huge challenges in designing novel operational geometries. Mono-pole and quasi-mono-pole antennas are seen to be the most compact and easily incorporate able solution for portable devices taking the advantages of printed circuit board (PCB) techniques. Most antennas of such type have symmetrical structures. It is possible to attain wider operating bandwidths by meeting symmetry conditions while chopping the antenna into halves for a compact structure. However, there is no generalized way of applying such a technique. The presented paper addresses this issue by proposing a common feeding technique that can be applied to any antenna which is miniaturized using its symmetrical structure. The proposed technique enables feeding the halved structure to achieve wider and better impedance matching than the reported full-size antennas. The theory of characteristic modes is applied to quasi-mono-pole structures to get an insight of the antennas mechanism. The radiation patterns are also correlated with modal current distributions to understand the radiation characteristics of the modified structure. Lastly, the method is implemented on some example antennas to illustrate its potential.
Planar Microstrip Bandpass Filter with Wide Dual Bands Using Parallel-Coupled Lines and Stepped Impedance Resonators
Jayaseelan Marimuthu;Amin M. Abbosh;Bassem Henin
PIER C , 2013, DOI: 10.2528/PIERC12110402
Abstract: A dual-band bandpass filter with wide and highly attenuated stopbands is designed using parallel coupled microstrip line (PCML) and stepped-impedance-resonators (SIRs). The proposed filter is composed of a pair of highly coupled PCML-SIR structure and a central resonator using a low impedance rectangular microstrip. Initially, the wide dual-band performance is achieved by creating a transmission zero between those two bands using a tightly coupled PCML-SIR with a suitable impedance ratio. Then, a low impedance resonator is placed between the pair of PCML-SIR to generate multiple resonant frequencies for a broadband performance. The simulated and measured results of those filters agree very well. The bandwidth of the first band in the developed filters extends from 1.75 GHz to 3.75 GHz with less than 0.3 dB insertion loss at the center of the band. The second band has a bandwidth that extends from 6.95 GHz to 8.75 GHz with less than 0.5 dB insertion loss at the center of that band. The stopband separating those two passband has more than 30 dB attenuation with transmission zero at 5.85 GHz.
Wideband Microwave Crossover Using Double Vertical Microstrip-CPW Interconnect
Yifan Wang;Amin M. Abbosh;Bassem Henin
PIER C , 2012, DOI: 10.2528/PIERC12071903
Abstract: The paper presents the design of a novel ultra-wideband microwave crossover for the use in microstrip circuits. The proposed structure includes a double microstrip-coplanar waveguide (CPW) vertical interconnect in single-layer substrate technology which allows an inclusion of a finite-width coplanar waveguide (CPW) on the top side of the substrate to achieve the required cross-link. The presented design is verified using the full-wave electromagnetic simulator Ansoft HFSS v.13 and experimental tests. The obtained experimental results show that in the frequency band of 3.2-11 GHz, the crossover has an isolation of 20 dB accompanied by insertion losses of no more than 1.5 dB.
Artificial Human Phantoms: Human proxy in testing microwave apparatus that have electromagnetic interaction with the human body
A. T. Mobashsher,A. M. Abbosh
Physics , 2015,
Abstract: In this manuscript, an effort is made in this review to address different state-of-the-art artificial tissue emulating (ATE) materials and phantom types for various operating frequencies, and fabrication procedures in order to have a better understanding of the pros and cons of various ATE phantoms which leads us to develop superior version of artificial human body substitute for various applications.
Experimental Assessment of Microwave Diagnostic Tool for Ultra-Wideband Breast Cancer Detection
Aslina Abu Bakar;David Ireland;Amin M. Abbosh;Yifan Wang
PIER M , 2012, DOI: 10.2528/PIERM11122102
Abstract: An ultra-wideband microwave imaging system that employs a heterogeneous breast phantom and covers the ultra-wideband (UWB) frequency range (3.1 GHz to 10.6 GHz) is presented. The platform scanning system allows monostatic and bistatic mode of operation. In this work, developed heterogeneous phantoms are used to mimic the realistic breast tissues. A utilized tapered slot antenna array allows for a high resolution hemispherical scan, achieved by rotating the imaged object on a turntable. Full design details of the scanning system and the utilized post-processing algorithm are explained. To validate the reliability of the presented system, the results of several imaging cases, including the challenging low dielectric contrast case, are presented.
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