A. Abbosh

University of Queensland, Brisbane, Queensland, Australia

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Publications (239)168.89 Total impact

  • Yuezhou Li, Amin Abbosh
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    ABSTRACT: A new type of pattern-reconfigurable reflectarray phased by reconfigurable unit cells that are centrally controlled by a laptop is presented. The proposed reflectarray with single-layer radiators employs a phasing element formed by a fixed-size circular ring attached by a variable-length arc phase delay line controlled by positive-intrinsic-negative diodes. The biasing network of the diodes is properly designed to minimise the interference between the radiating structure and the biasing circuit. To that end, the biasing circuit is placed on a substrate layer below the ground plane whereas the PIN switching diodes are embedded within radiators. The biasing signal is transmitted to the switching elements at the top layer using vias that penetrate the thin substrate layer, the foam layer and the ground plane. Investigations are carried out to verify the performances of the phasing element using a waveguide simulator. A reflectarray, which includes a C-band offset fed 8 × 8 elements, is configured to switch its main beam between 20° and 30° from the broadside direction. A biasing control unit is added to the fabricated reflectarray and activated using a laptop. The measured radiation patterns of the proposed reflectarray demonstrate a beam-switching characteristic from the broadside direction, which confirm the proposed design method.
    IET Microwaves Antennas & Propagation 05/2015; 9(7):664-671. DOI:10.1049/iet-map.2014.0227 · 0.97 Impact Factor
  • A. Zamani, S.A. Rezaeieh, A.M. Abbosh
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    ABSTRACT: A frequency-domain algorithm for the early detection of lung cancer is presented. The algorithm predicts the distribution of scattered fields inside the imaged domain (torso) using the measured fields around that domain. That prediction is based on using the first-order Bessel function of the first kind to relate the fields outside the imaged domain to the fields inside that domain. The predicted field distribution shows the relative differences between the dielectric properties of tissues within the torso and thus enables detecting lung cancer, which has a significantly larger dielectric constant that the lung’s healthy tissues. To validate the proposed algorithm, an integrated imaging system, which includes a three-dimensional slot-rotated antenna that circularly scans an artificial torso phantom using the band 1.5–3 GHz, a wideband microwave transceiver and a laptop for control, processing and image generation, is built. The obtained experimental results confirm the reliability of the proposed method in lung cancer detection. http://digital-library.theiet.org/content/journals/10.1049/el.2015.1402
    Electronics Letters 05/2015; 51(10). DOI:10.1049/el.2015.0230 · 1.07 Impact Factor
  • IET Microwaves Antennas & Propagation 04/2015; 9(5):486-494. DOI:10.1049/iet-map.2014.0365 · 0.97 Impact Factor
  • H. Zhu, A. Abbosh
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    ABSTRACT: A tunable bandpass filter with wide tuning ranges for both the centre frequency and bandwidth is presented. The filter is based on using a ring resonator connected to a short-ended coupled-line structure. Two transmission zeros are generated in the upper stopband resulting in a sharp cutoff and harmonic suppression across a wide stopband. A thorough procedure is used to analyse the proposed filter. A prototype is fabricated and tested. The achieved results indicate a wide centre frequency and bandwidth tuning ranges of 0.52–1.42 GHz and 90–320 MHz, respectively.
    Electronics Letters 04/2015; 51(7):568-570. DOI:10.1049/el.2015.0346 · 1.07 Impact Factor
  • Ummee T. Ahmed, Amin M. Abbosh
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    ABSTRACT: The design of a planar in-phase power divider for wideband applications is presented. The proposed divider uses a broadside coupled microstrip/slotline configuration with an improved isolation between the output ports using suitable isolation resistor. The proposed design is suitable for single layer integration as both the input and output ports are located at the same layer. Although the device can be used for any wideband application, the developed prototype is designed to operate within the band 2–5 GHz, which is used in microwave-based head imaging systems. The simulated and experimental results of the developed divider show equal power division with less than 0.5 dB of additional insertion loss, less than 2° of phase imbalance, more than 13 dB of isolation and more than 10 dB of return loss over the band 2.3–4.7 GHz. It has a compact size with an overall dimension of 30 × 30 mm2. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:789–791, 2015
    Microwave and Optical Technology Letters 04/2015; 57(4). DOI:10.1002/mop.28959 · 0.62 Impact Factor
  • Source
    Ahmed Toaha Mobashsher, Amin Abbosh
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    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.
    IEEE Antennas and Propagation Magazine 03/2015; 57(2). DOI:10.1109/MAP.2015.2414488 · 1.15 Impact Factor
  • Source
    Ahmed T. Mobashsher, Amin M. Abbosh
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    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.
    IEEE Microwave Magazine 03/2015; 16(6). DOI:10.1109/MMM.2015.2419772 · 1.67 Impact Factor
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    ABSTRACT: The effect of noise on the ability to detect strokes in the human head using microwave-based systems is investigated using both simulations and measurements. The simulations, which are implemented using the full-wave electromagnetic solver (CST), utilise a realistic numerical head model generated from magnetic resonance imaging slices. On the other hand, the experiments are performed using a wideband microwave system with a frequency range of 1-4 GHz. The experiments use a head phantom consisting of materials that accurately emulate (within 3% of reported properties of human brain tissues) the main tissues found in the human brain. It is shown, in both of the simulations and measurements, that a minimum signal-to-noise ratio of around 10 dB is required to accurately detect the presence of a stroke. Below this level, the microwave-based system either does not detect or falsely indicates the location of the stroke. Based on the presented results, the required microwave power to achieve acceptable detection is well within the recommended safe levels.
    IET Microwaves Antennas & Propagation 02/2015; 9(3):200-205. DOI:10.1049/iet-map.2014.0109 · 0.97 Impact Factor
  • S. Ahdi Rezaeieh, A. Zamani, A. M. Abbosh
    IEEE Antennas and Wireless Propagation Letters 01/2015; 14:910-914. DOI:10.1109/LAWP.2014.2386852 · 1.95 Impact Factor
  • He Zhu, Yifan Wang, A.M. Abbosh
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    ABSTRACT: A broadband microwave crossover with planar structure and compact size is proposed. It is composed of four pairs of parallel-coupled microstrip lines terminated with short-ended stubs. The utilised structure is analysed using a second-order even/odd-mode method, which shows that the centre frequency and bandwidth of the passband are defined by the length and coupling factor of the coupled lines, respectively. The proposed design is verified using both full-wave simulations as well as experiments on two prototypes. The achieved results of the two designs indicate fractional bandwidths of 12.5 and 25% with less than 0.8 dB of insertion loss, more than 17 dB of return loss, more than 18 and 12 dB of isolation and a flat group delay with less than 0.4 ns of deviation.
    IET Microwaves Antennas & Propagation 01/2015; 9(1):79-85. DOI:10.1049/iet-map.2014.0088 · 0.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A wideband antenna with unidirectional radiation is designed for lower ultra-high frequency (UHF) band, which is utilised in medical diagnostic systems, in addition to telecommunications, such as UHF television channels, WiMax, cognitive radio, radio frequency identification, mobile digital TV and CDMA/GSM800. In medical imaging, there are additional antenna design requirements, such as compact size, wide operating bandwidth and unidirectional radiation. A combination of dual monopole feeding, meandering and folding techniques is used to realise the required frequency band and directivity for the antenna, while reducing its size. The final design has the compact size of 0.23λ × 0.08λ × 0.08λ (λ is the wavelength of the lowest measured operating frequency of the antenna), a wide measured operating bandwidth of 50% (590-985 MHz), a peak gain of 3.6 dBi and a measured efficiency of more than 89% over the band of operation. The designed antenna is then used with a compact microwave transceiver, and proper data acquisition and processing algorithms to build a system for the early detection of congestive heart failure. The system is tested using a realistic artificial human torso.
    IET Microwaves Antennas & Propagation 11/2014; 8(14):1218-1227. DOI:10.1049/iet-map.2014.0340 · 0.97 Impact Factor
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    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. DOI:10.1109/TAP.2014.2342756 · 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. DOI:10.1109/TMTT.2014.2342669 · 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. DOI:10.1049/el.2014.1214 · 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. DOI:10.1049/el.2014.0616 · 1.07 Impact Factor
  • Source
    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). DOI:10.1002/mop.28229 · 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). DOI:10.1002/mop.28247 · 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. DOI:10.1109/TAP.2013.2296323 · 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. DOI:10.1109/TCPMT.2013.2277587 · 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. DOI:10.1109/LMWC.2013.2293658 · 2.24 Impact Factor

Publication Stats

2k Citations
168.89 Total Impact Points

Institutions

  • 2005–2014
    • University of Queensland
      • School of Information Technology and Electrical Engineering
      Brisbane, Queensland, Australia
  • 2006–2011
    • University of Mosul
      • • College of Electronic Engineering
      • • Department of Electrical Engineering
      Mosul, Muhafazat Ninawa, Iraq
  • 2006–2010
    • Griffith University
      • • Centre for Wireless Monitoring and Applications
      • • School of Engineering
      Southport, Queensland, Australia
  • 2007
    • University of the South Pacific
      • School of Engineering and Physics
      Suva, Central, Fiji