A.M. Abbosh

University of Queensland, Brisbane, Queensland, Australia

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Publications (113)83.06 Total impact

  • Samah Mustafa, A.M. Abbosh, P.T. Nguyen
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    ABSTRACT: A fourth order Debye model is derived using genetic algorithms to represent the dispersive properties of the 17 tissues that form the human head. The derived model gives accurate estimation of the electrical properties of those tissues across the frequency band from 0.1 GHz to 3 GHz that can be used in microwave systems for head imaging. A convolution-based three-dimensional finite-difference time-domain (3D-FDTD) formulation is implemented for modeling the electromagnetic wave propagation in the dispersive head tissues whose frequency dependent properties are represented by the derived fourth-order Debye model. The presented results show that the proposed 3D-FDTD and fourth-order Debye model can accurately show the electromagnetic interaction between a wide band radiation and head tissues with low computational overhead and more accurate results compared with using multi-pole Cole-Cole model.
    IEEE Transactions on Antennas and Propagation 03/2014; 62(3):1354-1361. · 2.33 Impact Factor
  • Beada'a J. Mohammed, Amin M. Abbosh
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    ABSTRACT: The fabrication of a realistic head phantom to test microwave‐based brain imaging is presented. Low‐cost mixtures of materials are used to construct the main head tissues (hair, scalp, skull, cerebral spinal fluid, grey, and white matters). The properties of the fabricated tissues are stable over a long time and agree well with the measured data available in the literature across the band of interest (1–4 GHz). Because no data is available concerning the electrical properties of human hair, extensive measurements are done to find the properties of real and artificial wig hair across the band 0.2–20 GHz. A wig is found to emulate reasonably well the properties of real hair. It is thus used as part of the fabricated phantom. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:979–982, 2014
    Microwave and Optical Technology Letters 01/2014; 56(4). · 0.59 Impact Factor
  • Bassem Henin, Amin Abbosh
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    ABSTRACT: The design of a wideband in‐phase power divider/combiner is presented. It uses a three‐line coupled structure with slotted ground and 100 Ω isolation resistor for an increased band using easy‐to‐manufacture dimensions. The operation of the device and its design procedure re explained for an enhanced isolation, almost ideal phase performance, and a balanced power division between its two output ports. The simulated and experimental results of the developed 1.5 × 1.5 cm2 power divider show 90% fractional bandwidth assuming 10 dB return loss as a reference with less than ±1° phase imbalance between the output ports. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1010–1012, 2014
    Microwave and Optical Technology Letters 01/2014; 56(4). · 0.59 Impact Factor
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    ABSTRACT: A wideband microwave system for head imaging is presented. The system includes an array of 16 corrugated tapered slot antennas that are installed on an adjustable platform. A switching device is used to enable the antennas to sequentially send a wideband 1-4 GHz microwave signal and capture the backscattered signals. Those signals are recorded using suitably designed virtual instrument software architecture. To test the capability of the system to detect brain injuries, a low-cost mixture of materials that emulate the frequency-dispersive electrical properties of the major brain tissues across the frequency band 1-4 GHz are used to construct a realistic-shape head phantom. A target that emulates a realistic hemorrhage stroke is fabricated and inserted in two different locations inside the fabricated head phantom. A preprocessing algorithm that utilizes the symmetry of the two halves of human head is used to extract the target response from the background reflections. A post-processing confocal algorithm is used to get an image of the phantom and to accurately detect the presence and location of the stroke.
    IEEE Transactions on Instrumentation and Measurement 01/2014; 63(1):117-123. · 1.71 Impact Factor
  • Y. Wang, A.M. Abbosh, B. Henin, P.T. Nguyen
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    ABSTRACT: A synthetic bandwidth radar as an approach to build ultra-wideband (UWB) imaging systems is presented. The method provides an effective solution to mitigate the challenges of UWB antenna's implementation with ideal performance. The proposed method is implemented by dividing the utilized UWB into several channels, or sub-bands, and designing an antenna array that includes a number of antennas equal to the number of channels. Each of those antennas is designed to have excellent properties across its corresponding channel. As part of the proposed approach, a two-stage calibration procedure is used to accurately estimate the effective permittivity of a heterogeneous imaged object at different angles and the phase center of each antenna for accurate delay time estimation. When imaging an object, each of the antennas transmits and captures signals only at its channel. Those captured signals are properly combined and processed to form an image of the target that is better than the current systems that use array of UWB antennas. The presented method is tested on breast imaging using the band 3–10 GHz via simulations and measurements on a realistic heterogeneous phantom.
    IEEE Transactions on Antennas and Propagation 01/2014; 62(2):698-705. · 2.33 Impact Factor
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    ABSTRACT: A novel broadband bandpass filter with multiple resonant modes based on parallel-coupled microstrip line is proposed. The required cutoff frequency and out-of-band performance are achieved by placing L-shaped capacitive cross-coupling open stubs at the middle resonator with appropriate dimensions. A compact broadband bandpass filter of dimensions 18 × 29 mm2 is fabricated and tested for performance confirmation. The proposed filter demonstrates a wide bandwidth (from 3 to 7 GHz), as well as excellent out-of-band performance with more than 25-dB rejection up to more than 12 GHz and sharp upper cutoff frequency due to the proper location of two transmission zeros. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1640–1644, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27637
    Microwave and Optical Technology Letters 07/2013; 55(7). · 0.59 Impact Factor
  • David Ireland, Amin Abbosh
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    ABSTRACT: Debye models for tissues found in the human head are presented. The parameters of the Debye models are optimized to measured data of different head tissues. Excellent consistency over the frequency band from 0.1 GHz to 5 GHz is shown with improved accuracy compared to current models using the Cole-Cole approximation. The auxiliary differential-equation based method is used to incorporate the derived models into a finite-difference time-domain program. The validity of the derived models are verified by comparing the fields produced in a realistic 2-D phantom head using a finite-difference time-domain program with the proposed Debye models, and a method of moments solver.
    IEEE Transactions on Antennas and Propagation 04/2013; 61(4):2352-2355. · 2.33 Impact Factor
  • Bassem Henin, Amin Abbosh
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    ABSTRACT: The design of a planar four-port microstrip crossover is presented. The design starts by using a half-wavelength square patch and two sets of orthogonal feeding lines. To achieve a wideband performance, four circular slots are introduced in the square patch. A parametric analysis is used to investigate the effect of the utilized slots. Full-wave simulations and measurements are used to validate the proposed design. The simulated and measured data show less than 1 dB insertion loss, more than 10 dB return loss, more than 19 dB isolation, and about 0.2 ns group delay deviation across the band from 2.1 to 2.75 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:439–443, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27335
    Microwave and Optical Technology Letters 02/2013; 55(2). · 0.59 Impact Factor
  • Yifan Wang, A.M. Abbosh, B. Henin
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    ABSTRACT: The design of a novel wideband microwave crossover is presented. The proposed structure is fully compatible with microstrip circuits as it is printed on one side of a single-layer substrate. The structure is made up of a circular microstrip patch connected to a ring resonator. The operation of the presented design is explained by deriving the equivalent circuit model using the second-order even-odd mode excitations. The derived model is verified by full-wave electromagnetic simulations. A prototype is designed, developed, and tested. The results show a crossover with more than 18 dB of isolation, less than 0.5 dB insertion loss, and less than 0.25 ns deviation in the group delay across the band from 2.15 GHz to 3.35 GHz (44% fractional bandwidth).
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 01/2013; 3(10):1771-1777. · 1.26 Impact Factor
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    ABSTRACT: A planar antenna array that includes 12 corrugated tapered slot elements for use in ultrawideband (UWB) biomedical microwave imaging systems is presented. The used corrugate tapered slot antenna has a compact size, low profile, moderate gain, and distortionless performance in the time domain. The array is immersed in a carefully designed matching liquid of suitable dielectric constant to improve the matching between the array and the imaged object, and thus, to increase the dynamic range of the imaging system. A suitable platform is designed and fabricated to accommodate the array, breast phantom, and a coupling liquid for the case of UWB breast imaging. The design of the whole system is optimized using trust-region framework method in the simulation tool CST Microwave Studio. The performance of the designed array is confirmed via measurements in a realistic imaging environment. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013. © 2013 Wiley Periodicals, Inc.
    International Journal of RF and Microwave Computer-Aided Engineering 01/2013; 23(1):59-66. · 0.75 Impact Factor
  • Yuezhou Li, Amin Abbosh
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    ABSTRACT: An electronically controlled phasing element for a beam-steered single-layer microstrip reflectarray operating at 4 GHz is presented. The phasing element is formed by a printed circular ring equipped with a variable-length arc stub. The reconfigurable design is accomplished by including an open gate p-i-n transistor in the variable-length stub to offer a 1-bit beam-steering ability. Full-wave electromagnetic simulations and measurements are performed to prove the linear phase performance of the proposed cell including the effect of the utilized active chip and its biasing circuit. Those results indicate the high isolation between the phase performance of the utilized cell between the on and off states of the p-i-n switches.
    IEEE Antennas and Wireless Propagation Letters 12/2012; · 1.67 Impact Factor
  • Yuezhou Li, M.E. Bialkowski, A.M. Abbosh
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    ABSTRACT: The design of a single-layer reflectarray, which employs a new phasing element in the form of a fixed-size circular ring and a variable-length open-circuited stub, is presented. The array is developed on a thin substrate supported by a thick foam material. Investigations are performed to obtain a linear reflection phase as a function of the stub's length when the element operates in a unit cell. This goal is achieved by a suitable choice of the ring's radius and width and the stub's width. In order to validate the simulated element's reflection phase behavior, a waveguide simulator is manufactured to perform experimental tests. The phasing element offering best linear phase characteristics is used to design an -band offset fed 13×13 element reflectarray pointing at 20° from the broadside direction. Full-wave simulations performed using CST Microwave Studio show desired radiation characteristics of the designed array antenna. The simulated performance is confirmed by experimental tests performed on the fabricated reflectarray prototype showing a 17.8% 3-dB gain drop bandwidth.
    IEEE Transactions on Antennas and Propagation 09/2012; 60(9):4183 - 4189. · 2.33 Impact Factor
  • A. M. Abbosh
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    ABSTRACT: AbstractA microwave crossover using a dual‐mode microstrip patch is presented. The patch is designed to operate at two orthogonal modes. Each of those modes is used to couple a pair of face‐to‐face ports. The isolation between the two orthogonal modes is enhanced by using symmetrical slits in the microstrip patch. The proposed crossover has the main features of high‐power handling capability and distortionless response due to its extremely low group delay deviation. A prototype is designed to operate at the WLAN band from 5.15 to 5.85 GHz. The simulated and measured results indicate less than 0.06 ns deviation in the group delay, less than 1 dB insertion loss, more than 13 dB return loss and more than 12 dB isolation across the whole band. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2077–2079, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27028
    Microwave and Optical Technology Letters 09/2012; 54(9). · 0.59 Impact Factor
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    ABSTRACT: The article reports the design of an ultrawideband quadrature power divider in uniplanar microstrip technology. The proposed device uses the conventional Wilkinson power divider with one of its output arms equipped with a double wireless via acting as a phase adjusting circuit. The device is manufactured showing a wide bandwidth in terms of return loss, isolation, power division, and a differential phase shift of 90° across the frequency band of 3–8 GHz. Its compact size and good performance makes it suitable for use in wideband-balanced amplifiers. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:300–305 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26519
    Microwave and Optical Technology Letters 02/2012; 54(2). · 0.59 Impact Factor
  • A.M. Abbosh
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    ABSTRACT: A method to design microstrip bandpass filters with ultra-wideband (UWB) performance, wide stopband, and practical dimensions is presented. According to the proposed method, three subsections of different lengths and coupling factors are connected to form a stepped-impedance parallel-coupled microstrip structure. A theoretical model is derived and used to find the optimum length and coupling factor for each of those subsections for an UWB passband and suppressed second and third harmonic responses in the stopband. The required performance is realized by generating and proper positioning of three transmission zeros in the upper stopband and three transmission poles in the passband. The derived model shows that the total length of the three-subsection coupled structure is one-third of the effective wavelength at the center of the passband. The theoretical model is used to find the required design values for the whole structure. The presented method is validated by building a bandpass filter that has a passband from 3.1 to 10.6 GHz with less than 1-dB insertion loss and a wide upper stopband that extends up to 28 GHz.
    IEEE Transactions on Microwave Theory and Techniques 01/2012; 60(1):31-38. · 2.23 Impact Factor
  • B.J. Mohammed, A.M. Abbosh, D. Ireland
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    ABSTRACT: A brain imaging system that uses a circular array tapered slot wideband antennas is reported. The antenna utilized in the array is a corrugated microstrip-fed tapered slot antenna of compact dimensions (24 mm × 24 mm) immersed in a suitable coupling liquid for improved matching with the brain tissues. To protect the antenna elements from the harmful effects of the coupling liquid a dielectric sheets are used to cover the radiating elements. The proposed circular array includes ten wideband antenna elements that are designed to operate efficiently across the band from 1 GHz to 4 GHz. The developed array is tested using a phantom that emulates a stroke affected brain.
    Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE; 01/2012
  • A. M. Abbosh
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    ABSTRACT: A compact three-way power divider with ultra-wideband (UWB) performance is presented. The proposed device utilizes a simple and low-cost broadside-coupled microstrip-coplanar waveguide structure. The conformal mapping technique is used to find the dimensions of the device. The simulated and measured output power, return loss, and isolation validate the suitability of the proposed divider for the UWB applications that operate across the frequency band from 3.1 GHz to more than 10.6 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:196–199, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26492
    Microwave and Optical Technology Letters 01/2012; 54(1). · 0.59 Impact Factor
  • B.J. Mohammed, D. Ireland, A.M. Abbosh
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    ABSTRACT: A microwave imaging system for the potential detection of tumours in breast tissues using a planar array that employs 6 x 2 compact tapered slot antenna elements is reported. In this system, the breast is placed on a plastic sheet and slightly compressed to take a semi-rectangular shape; this allows for accurate image reconstruction using a planar array. Both the array and the phantom are immersed in a coupling medium to increase the signal penetration, and thus, the dynamic range of the system. In order to quantity the effect of changing the number of elements and their positions in the array, image reconstruction is undertaken with three different configurations. That is with 6- and 12-array elements and an additional 908 rotation of the phantom. To test the designed system a suitable combination of materials are used to fabricate a low-density, heterogeneous breast phantom. Two- and three-dimensional versions of a confocal imaging algorithm are used to construct the images and metrics are proposed to evaluate the quality of the image. Single and multiple embedded targets are shown to be resolved using the proposed array and imaging algorithm in either two or three dimensions.
    IET Microwaves Antennas & Propagation 01/2012; 6(12):1311-1317. · 0.84 Impact Factor
  • B.J. Mohammed, A.M. Abbosh, D. Ireland
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    ABSTRACT: In this paper, we investigate the possibility of using array of wideband antennas to differentiate between the two kinds of brain stroke: ischemic and hemorrhagic. Wideband antennas arranged as a circular array surrounding a human head and immersed in a coupling medium are used to monitor a suspected stroke area. The proposed method is based on comparing the reflection coefficients of any pair of antennas located symmetrically around the head. The simulated results indicate a promising method of using the variation in the reflection coefficient of the antennas to give a quick differentiation between different head strokes, which is a must for any possibility of a patient survival.
    Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE; 01/2012
  • Y. Wang, M. E. Bialkowski, A. M. Abbosh
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    ABSTRACT: The letter describes double microstrip-slot transitions for use in planar ${\pm} 90^{\circ}$ phase shifters. The described devices exhibit broadband performance and offer compatibility with ordinary microstrip circuits. Full-wave EM simulation results show a phase shift of ${\pm} 90^{\circ}$ ${\pm} 7^{\circ}$ over the frequency band of 3.1–12.0 GHz when compared with a suitably chosen section of microstripline. The observed differential phase shift is accompanied by return losses of not less than 14 dB and insertion losses between 0.7 to 1.5 dB in the band 3.1–11.0 GHz. The simulated performance is confirmed by experimental results of ${\pm} 90^{\circ} {\pm} 8^{\circ}$ phase shift, return loss not less than 14 dB and insertion loss between 0.5 and 1.8 dB in the frequency band of 3.1–11.0 GHz.
    IEEE Microwave and Wireless Components Letters - IEEE MICROW WIREL COMPON LETT. 01/2012; 22(2):58-60.

Publication Stats

636 Citations
83.06 Total Impact Points

Institutions

  • 2005–2013
    • University of Queensland
      • School of Information Technology and Electrical Engineering
      Brisbane, Queensland, Australia
  • 2006–2009
    • Griffith University
      • • School of Engineering
      • • Centre for Wireless Monitoring and Applications
      Southport, Queensland, Australia
  • 2007
    • University of the South Pacific
      • School of Engineering and Physics
      Suva, Central, Fiji