A.M. Abbosh

University of Queensland, Brisbane, Queensland, Australia

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Publications (128)104.2 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A three-dimensional antenna based on a combination of loop and dual monopole structures with parasitic elements is presented. The antenna is specifically designed for a microwave system aimed at the early detection of congestive heart failure. The antenna is first designed as a planar structure and then folded over optimally defined folding lines to properly alter the path and phase of the surface currents for a unidirectional radiation and compact size as needed for the detection system. A prototype antenna of size $0.29lambda times 0.08lambda times 0.08lambda $ (where, $lambda $ is the wavelength of the lowest resonant frequency) is developed to cover the band required in the targeted application. The measured results indicate 53% fractional bandwidth (580 – 1000 MHz), 6-8 dB front to back ratio, and 3-5 dBi gain. The antenna is then used to build a heart failure detection system, which also includes a compact microwave transceiver, a processing and image reconstruction algorithm based on the synthetic aperture focusing technique, and a display unit. The system is used to successfully detect an early case of congestive heart failure in an artificial torso phantom that includes the main torso organs (lungs, heart, ribs, and fat).
    IEEE Transactions on Antennas and Propagation 10/2014; 62(10):5375-5381. · 2.46 Impact Factor
  • Source
    A.T. Mobashsher, A.M. Abbosh, Yifan Wang
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    ABSTRACT: A portable microwave system to detect traumatic brain injuries is described. The wideband system utilizes a unidirectional antenna, microwave transceiver, and processing and image reconstruction algorithms. The utilized antenna is designed to have a compact three-dimensional (3-D) structure using a slotted dipole element and a folded parasitic structure. It attains directional radiation patterns with an average 9-dB front-to-back ratio and 102.2% fractional bandwidth covering the band 1.1–3.4$~$ GHz, which is suitable for head imaging. To test the system, a realistic head phantom, which attains accurate internal and external anatomical structure and electrical properties, is fabricated by a 3-D printer using a detailed numerical model. Targets imitating the properties of bleeding are inserted at different positions in the fabricated head phantom to emulate brain injury scenarios. The integrated system is used in a virtual arrayed monostatic radar approach to detect the injuries. Using data sets recorded at 32 antenna positions around the head, a back projection algorithm is used to generate images of the scanned head. The achieved results demonstrate the feasibility of such a system as a portable module for brain injuries detection.
    IEEE Transactions on Microwave Theory and Techniques 09/2014; 62(9):1826-1836. · 2.94 Impact Factor
  • H. Zhu, A. Abbosh, L. Guo
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    ABSTRACT: A compact ultra-wideband in-phase power divider using a three-line coupled structure is proposed. The power division of the device depends on the coupling factors between the centreline and the two sidelines. For an enhanced isolation between the output ports, a 100 Ω chip resistor is connected between the ends of the two sidelines, whereas the end of the centre line is grounded. To verify the design, a prototype with 2:1 power division was fabricated and tested. The measured results validate the ultra-wideband performance with more than 12 dB return loss, more than 13 dB isolation and
    Electronics Letters 07/2014; 50(15):1081-1082. · 1.07 Impact Factor
  • Source
    A.T. Mobashsher, A. Abbosh
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    ABSTRACT: Microwave-based brain stroke detection demands low profile, compact, directive and wideband antennas for efficient imaging using portable systems. Using image theory of electromagnetics, the magnetic symmetry plane of a folded antenna is utilised for its miniaturisation to half of its original volume without sacrificing its penetration capability or radiation directivity. The antenna achieves 63% fractional bandwidth (1.25-2.4 GHz) with 3.5 dBi average gain along the direction of radiation. Both the near-field and far-field radiations are characterised to ensure the antenna's applicability in the detection system. Moreover, the radiation safety is also analysed since the antenna has to operate in close proximity to the head. The overall dimensions of the proposed antenna are 0.29λ0 x 0.12λ0 x 0.06λ0 (λ0 = lowest operating wavelength).
    Electronics Letters 06/2014; 50(12):850-851. · 1.07 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 04/2014; 56(4). · 0.62 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 04/2014; 56(4). · 0.62 Impact Factor
  • 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. · 2.46 Impact Factor
  • A.M. Abbosh
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    ABSTRACT: The design of an out-of-phase planar power divider/combiner operating over an octave frequency band is presented. The proposed device uses a modified single-section Gysel structure. The main features of the proposed device are simple and easy to package structure that does not use any slots in the ground plane, and the use of one isolation resistor that can be external to the packaging structure for efficient heat dissipation. The proposed device is suitable for high-power microwave modules and perfectly compatible with microstrip circuits. A complete design method is derived and validated. To make the device compact without jeopardizing its power capacity, a moderate meandering for the utilized transmission lines using an elliptical function is adopted. To compensate for the parasitic elements introduced in one of the signal paths due to meandering, the transmission line at the other path is elliptically tapered. The simulated and measured results of the developed device show one octave bandwidth with $180^{circ}pm 9^{circ}$ differential phase between the output ports and ${>}{rm 16}~{rm dB}$ of isolation. The final design has a compact area of ${<}{rm 1}/{rm 10}$ of the squared guided wavelength.
    IEEE Transactions on Components, Packaging, and Manufacturing Technology 03/2014; 4(3):465-471. · 1.24 Impact Factor
  • L. Guo, A. Abbosh
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    ABSTRACT: Compact planar phase shifters with wide range of differential phase shift across ultra-wideband frequency are proposed. To achieve that performance, the devices use broadside coupled structure terminated with open-ended or short-ended stubs. The theory of operation for the proposed devices is derived. To validate the theory, several phase shifters are designed to achieve a differential phase ranging from ${-}180^{circ}$ to 180$^{circ}$ . Moreover, three prototypes are developed and tested. The simulated and measured results agree well with the theory and show less than 7$^{circ}$ phase deviation and 1.4 dB insertion loss across the band 3.1–10.6 GHz.
    IEEE Microwave and Wireless Components Letters 03/2014; 24(3):167-169. · 2.24 Impact Factor
  • L. Guo, A. Abbosh, H. Zhu
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    ABSTRACT: A compact in-phase power divider utilising a stepped-impedance three-line coupled structure and microstrip-to-slotline transitions is presented. The equivalent circuit of the structure is used to predict the required dimensions for ultra-wideband performance. The length of the structure, excluding the input/output ports needed for the measurements, is around a quarter guided wavelength. The simulated and measured results for the two developed devices indicate equal in-phase power division with less than 0.1 dB and 2° amplitude and phase imbalances, respectively. The return loss at the three ports is more than 15 dB in one prototype, whereas the isolation is more than 13 dB in the other across the band from 3.1 to 10.6 GHz.
    Electronics Letters 02/2014; 50(5):383-384. · 1.07 Impact Factor
  • Source
    A.T. Mobashsher, A. Abbosh
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    ABSTRACT: Medical diagnostic systems demand wideband antennas with directive radiation patterns. In addition, portable systems require low profile and light weight antennas to be incorporated. These necessities of modern microwave-based diagnostic systems are addressed in this reported work. The antenna is built with two simple thoroughly printed structures connected to each other using two copper walls, forming a loop-like geometry. The top element is capacitively loaded with a pair of symmetrically placed slots and fed with a coplanar waveguide (CPW). The antenna works like a small loop in the lower resonating mode and as a folded-dipole in the higher modes. The antenna exhibits a 109% bandwidth with stable radiation patterns of an about 9 dB front-to-back ratio over most of the band with only a profile of 0.05λ (λ = wavelength at the lowest frequency). The measured and the simulated results show that the proposed antenna is suitable for wideband medical imaging systems.
    Electronics Letters 02/2014; 50(4):246-248. · 1.07 Impact Factor
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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 02/2014; 62(2):698-705. · 2.46 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
  • Source
    A.T. Mobashsher, Amin Abbosh
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    ABSTRACT: Wideband antennas operating at L-band are rapidly finding their applications in various microwave-based medical diagnostic systems. To increase signal penetration while working in a limited space, these systems require compact unidirectional antennas. To meet these requirements, a three-dimensional folded dipole antenna is presented. It is composed of a slot-loaded coaxially fed printed slab and a U-shaped copper structure that completes the folded dipole loop. An appropriate slot loading enables achieving significant improvements of the proposed design in terms of bandwidth, gain, and front-to-back ratio compared to the conventional folded dipole antenna. A parametric analysis is performed for a deep understanding of the antenna's mechanism. A fabricated prototype demonstrates 57% fractional bandwidth, centered at 1.44 GHz with an average gain of 3.7 dBi over that band. The antenna has a directional radiation pattern with around 9 dBi front-to-back ratio and $-$10-dB cross-polarization levels along the boresight direction. The overall volume of the antenna is 0.24$,times,$0.10$,times ,$0.05 $lambda ^{3}$, where $lambda $ is the wavelength of the lowest operating frequency.
    IEEE Antennas and Wireless Propagation Letters 01/2014; 13:798-801. · 1.95 Impact Factor
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    ABSTRACT: Fluid accumulation inside the lungs, known as cardiac pulmonary edema, is one of the main early symptoms of congestive heart failure (CHF). That accumulation causes significant changes in the electrical properties of the lung tissues, which in turn can be detected using microwave techniques. To that end, the design and implementation of an automated ultrahigh-frequency microwave-based system for CHF detection and monitoring is presented. The hardware of the system consists of a wideband folded antenna attached to a fully automated vertical scanning platform, compact microwave transceiver, and laptop. The system includes software in the form of operational control, signal processing, and visualizing algorithms. To detect CHF, the system is designed to vertically scan the rear side of the human torso in a monostatic radar approach. The collected data from the scanning is then visualized in the time domain using the inverse Fourier transform. These images show the intensity of the reflected signals from different parts of the torso. Using a differential based detection technique, a threshold is defined to differentiate between healthy and unhealthy cases. This paper includes details of developing the automated platform, designing the antenna with the required properties imposed by the system, developing a signal processing algorithm, and introducing differential detection technique besides investigating miscellaneous probable CHF cases.
    Access, IEEE. 01/2014; 2:921-929.
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    ABSTRACT: A broadband circularly polarised (CP) antenna employing a deformed square loop radiator in combination with two spiraled monopoles is presented, for use in multiple ultra-high frequency applications. This combination of radiators provides a broad impedance matching bandwidth which is not accessible using any of these techniques alone. The antenna employs a uniplanar structure that is fed using a coplanar waveguide for simplicity of fabrication. A dual-resonance response is achieved by introducing two spiraled monopoles in combination with a square loop radiator. Subsequently, circular polarisation is achieved by introducing three conducting rectangles into the periphery of the square loop, forming a deformed loop radiator. The increase in the electrical length caused by the introduction of the three rectangles also improves the impedance matching of the antenna, providing a wide impedance bandwidth. The antenna exhibits a 45% (556-882 MHz) -10 dB impedance bandwidth, and a 21% (715-880 MHz) 3 dB axial ratio bandwidth. It has a compact size of 0.28λ × 0.28λ × 0.002λ at 582 MHz, which is the lowest resonant frequency of the antenna. Throughout the operating bands, the gain and radiation efficiency vary from 3.6 to 6.4 dBi and 85 to 90%, respectively.
    IET Microwaves Antennas & Propagation 01/2014; 8(4):263-271. · 0.97 Impact Factor
  • S. Ahdi Rezaeieh, A.M. Abbosh
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    ABSTRACT: A wideband folded antenna, which is specifically designed for an early heart failure detection system operating at the ultra-high frequency (UHF) band, is presented. The design procedure starts with a planar structure that includes a loop antenna, a dual monopole, and a loaded parasitic patch. To significantly reduce the size of the antenna and achieve directional radiation as needed for the intended application, the planar structure is folded to form a three-dimensional antenna with the dimensions $0.1lambdatimes 0.29lambdatimes 0.09lambda$ , where $lambda$ is the wavelength at the lowest operating frequency. The final tested antenna achieves a peak gain of 4.2 dBi, front-to-back ratio of 7–13 dB and efficiency of more than 87% over 62% fractional bandwidth (560–1060 MHz) at 10-dB return-loss reference. The antenna in addition to a compact microwave transceiver and an adjustable platform are then used to build a monostatic-radar-based heart failure detection system. The system is tested on an artificial torso phantom to verify the potential of such a system in the early detection of heart failure. The used imaging algorithm and obtained promising results are reported in the letter.
    IEEE Antennas and Wireless Propagation Letters 01/2014; 13:844-847. · 1.95 Impact Factor
  • Source
    A.T. Mobashsher, Amin Abbosh
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    ABSTRACT: A compact ultra-wideband (UWB) antenna with directional radiation is presented. The antenna has a low profile and does not need a large ground for its performance. The antenna is based on using a three-dimensional folded structure that is modified using semi-circular slots on bowtie-shaped elements. The antenna's mechanism, its design guidelines and its optimisation are described thoroughly. A prototype of the antenna is fabricated and measured for performance verification. The prototype shows 77% fractional bandwidth (centred at 2 GHz) based on 10 dB return loss reference. The equivalent overall size of the prototype is (λeff/3) × (λeff/4) × 0.07λeff (λeff = effective wavelength at the lowest resonant frequency), which proves the compactness of the antenna. The antenna shows unidirectional radiation pattern with around 15 dB front-to-back ratio, -20 dB cross-polarisation in the two principle planes and around 5 dBi gain. The antenna is prescribed for compact UWB applications that use the low 1-3 GHz frequency band.
    IET Microwaves Antennas & Propagation 01/2014; 8(3):171-179. · 0.97 Impact Factor
  • Source
    A.T. Mobashsher, A.M. Abbosh
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    ABSTRACT: An anatomically realistic human head phantom as a potential mean of experimentally validating microwave-based head imaging systems and other prominent applications is reported. Using an MRI-derived model, the phantom is 3-D-printed using a laser sintering material to represent the external tissue layers starting from the skull. The skull cavity is filled with the help of 3-D-printed molds with tissue-mimicking mixtures that are formed using low-cost ingredients. The included tissues are gray matter, white matter, Dura, CSF, eye, cerebellum, spinal cord, and blood. Our measurements indicate that the properties of the fabricated tissues are stable with time and agree with the real properties with less than 5% variation across the band 0.5-4 GHz, which is widely utilized in various imaging and mobile applications.
    IEEE Antennas and Wireless Propagation Letters 01/2014; 13:1401-1404. · 1.95 Impact Factor
  • IEEE Antennas and Wireless Propagation Letters 01/2014; 13:1753-1756. · 1.95 Impact Factor

Publication Stats

1k Citations
104.20 Total Impact Points

Institutions

  • 2005–2014
    • 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
    • University of Mosul
      • Department of Electrical Engineering
      Al Mawşil, Nīnawá, Iraq
  • 2007
    • University of the South Pacific
      • School of Engineering and Physics
      Suva, Central, Fiji