A. Abbosh

University of Queensland, Brisbane, Queensland, Australia

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Publications (249)158.62 Total impact

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    ABSTRACT: Pulmonary oedema is a common manifestation of various fatal diseases that can be caused by cardiac or non-cardiac syndromes. The accumulated fluid has a considerably higher dielectric constant compared to lungs' tissues, and can thus be detected using microwave techniques. Therefore, a non-invasive microwave system for the early detection of pulmonary oedema is presented. It employs a platform in the form of foam-based bed that contains two linear arrays of wideband antennas covering the band 0.7-1 GHz. The platform is designed such that during the tests, the subject lays on the bed with the back of the torso facing the antenna arrays. The antennas are controlled using a switching network that is connected to a compact network analyzer. A novel frequency-based imaging algorithm is used to process the recorded signals and generate an image of the torso showing any accumulated fluids in the lungs. The system is verified on an artificial torso phantom, and animal organs. As a feasibility study, preclinical tests are conducted on healthy subjects to determinate the type of obtained images, the statistics and threshold levels of their intensity to differentiate between healthy and unhealthy subjects.
    Scientific Reports 09/2015; 5:14047. DOI:10.1038/srep14047 · 5.58 Impact Factor
  • Ummee T. Ahmed · Amin M. Abbosh
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    ABSTRACT: The design of a planar out‐of‐phase power divider with broadband behavior is presented. The proposed device uses broadside coupled microstrip‐slotline‐microstrip transitions at the input port and coupled microstrip lines with shunt open‐ended stubs at the output ports to extend the impedance matching bandwidth at three ports of the device. Moreover, a dumbbell‐shaped slot is located underneath the coupled lines and shunted with a proper chip resistor to improve the isolation between the output ports. The utilized structure is suitable for single layer integration as both the input and output ports are located at the same layer. Following a proper theoretical method based on the even‐odd mode approach and slotline design guidelines, a prototype of the presented device aiming to operate across the band 1–3 GHz is designed, built, and tested. The developed device has overall dimensions of 30 mm × 60 mm using the substrate Rogers RO4003 (dielectric constant = 3.38 and thickness = 0.406 mm). While the device can be used for any wideband application, the developed prototype is designed to operate within the band 1–3 GHz, which is used in most microwave‐based medical imaging applications. The achieved simulated and experimental results show 100% fractional bandwidth (1.1–3.3 GHz) assuming 15 dB of isolation as the reference. The proposed device has equal power division between the two output ports with less than 0.2 dB amplitude imbalance. Moreover, the phase difference between the signals at the two output ports is 180° ± 1° across the frequency band 1–3.5 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2216–2218, 2015
    Microwave and Optical Technology Letters 09/2015; 57(9). DOI:10.1002/mop.29296 · 0.57 Impact Factor
  • P.T. Nguyen · Amin Abbosh · Stuart Crozier
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    ABSTRACT: A technique for noninvasive microwave hyperthermia treatment for breast cancer is presented. In the proposed technique, electromagnetic focusing on patient-specific breast models is implemented to concentrate the power at the tumor position while keeping the power levels at other positions (healthy tissues) at minimum values. This step is realized by optimizing phase excitations of the utilized antenna elements. In the next step, a thermal analysis is used to determine the scaling factor of the antennas’ excitation amplitudes to realize the required temperature at the tumor position. A closed-loop procedure ensures that there are no hot spots in any of the healthy tissues. The technique is tested in a realistic environment which includes three-dimensional breast models and antenna arrays. The presented results on fatty and dense breast models using two types of directional antennas validate the proposed technique. The investigations across wide frequency bands indicate that the frequencies around 4.2 GHz and 4.5 GHz are optimum values for the hyperthermia treatment of dense and fatty breasts, respectively.
    IEEE Transactions on Antennas and Propagation 08/2015; DOI:10.1109/TAP.2015.2463681 · 2.18 Impact Factor
  • U. T. Ahmed · A. M. Abbosh
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    ABSTRACT: A planar in-phase power divider with extreme wideband behavior using modified Wilkinson design is presented. Instead of using T-junction at the input port of the traditional design, the proposed divider uses broadside coupled microstrip to slotline configuration. Moreover, the impedance matching of the output ports is significantly improved across several octaves bandwidth using three binomial sections, whereas the isolation between those ports is enhanced across that band using three isolation resistors. The utilized structure is suitable for single layer integration as both the input and output ports are located at the same layer. A prototype of the presented device is designed using a proper theoretical approach, built, and tested. The developed device has a compact size with an overall dimension of 40 × 55 mm2 using the substrate Rogers RO4003 (dielectric constant = 3.38, thickness = 0.406 mm). While the device can be used for any wideband application, the developed prototype is designed to operate within the band 1–7 GHz, which is used in most microwave-based medical imaging applications. The achieved simulated and measured results show that the proposed device has equal power division between the two output ports with less than 0.2-dB amplitude imbalance, more than 10-dB return loss and 15-dB isolation, and less than 2° phase difference between the two output signals across the extremely wide frequency band 1.2–7 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1799–1802, 2015
    Microwave and Optical Technology Letters 08/2015; 57(8). DOI:10.1002/mop.29187 · 0.57 Impact Factor
  • Electronics Letters 07/2015; 51(15):1144-1146. DOI:10.1049/el.2015.1652 · 0.93 Impact Factor
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    ABSTRACT: A slot-loaded meandered loop antenna for congestive heart failure (CHF) detection system is presented. To meet the requirements for a CHF detection system, the antenna is designed to have a compact size, wideband at the ultra-high frequency band and unidirectional radiation. To that end, several techniques are applied to the main utilized structure, which is a conventional loop antenna. To lower the resonant frequency and enhance the directivity within a compact size, the loop is capacitively loaded using a pair of slots. To compensate for the effect of the capacitive coupling on the input impedance matching, an inductive reactance is added by meandering the loop’s structure. With the applied modifications, the proposed antenna has a compact size of ${0.21} times 0.21$ with respect to the wavelength at the lowest operating frequency. The realized dimension represents only a quarter of the size of its counterpart planar designs. The proposed antenna achieves a wide measured fractional bandwidth of 50% (0.66–1.1 GHz), 9 dB peak front-to-back ratio and 4.1 dBi gain. The antenna is then used as part of a CHF detection system that also includes a compact transceiver, scanning platform, and laptop for control and processing. Using a suitable frequency–domain processing and imaging algorithm, the system successfully detects an early CHF in an artificial torso phantom.
    IEEE Transactions on Antennas and Propagation 07/2015; DOI:10.1109/TAP.2015.2457935 · 2.18 Impact Factor
  • 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 · 0.91 Impact Factor
  • Source
    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 · 0.93 Impact Factor
  • A.M. Abbosh · U.T. Ahmed
    Electronics Letters 05/2015; 51(11). DOI:10.1049/el.2015.0595 · 0.93 Impact Factor
  • IET Microwaves Antennas & Propagation 04/2015; 9(5):486-494. DOI:10.1049/iet-map.2014.0365 · 0.91 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 · 0.93 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 · 0.57 Impact Factor
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    ABSTRACT: Convex optimization provides a method of minimization of a convex objective function subject to a convex domain imposed upon it by the problem. For microwave imaging in medical applications, such as head imaging, this technique is seldom investigated. In this paper, a microwave-based head imaging method based on convex optimization is presented. Convex optimization is used to successfully estimate the distribution of relative permittivity of the imaged objects at different directions and thus to improve the quality of the obtained microwave image. The obtained results using 32 antennas surrounding a realistic head model compare favorably with the images from using the traditional microwave head imaging algorithm, which assumes a certain fixed average permittivity for the whole imaged head. The results show that the target representing a bleeding inside the head is properly recovered using the proposed optimization despite using wide range of initial average permittivity values. However, the quality of images produced using the traditional approach depends strongly on the assumed average permittivity.
  • 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 · 1.13 Impact Factor
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    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 · 1.32 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 · 0.91 Impact Factor
  • A.T. Mobashsher · A. Abbosh
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    ABSTRACT: A microwave head imaging prototype to detect intracranial hemorrhage is presented. The prototype system comprises of a compact ultra-wideband (UWB) antenna, custom-made transceiver and an image processing unit. The system is experimentally tested on a realistic three-dimensional (3D) printed human head phantom. A confocal image processing algorithm based on delay and sum approach is used to rapidly map the scanned layer of the head phantom. The low-cost, fast application, prompt detection and portability features of the proposed model make it a strong candidate to be used by the first response paramedics.
  • 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 · 0.91 Impact Factor
  • IEEE Antennas and Wireless Propagation Letters 01/2015; DOI:10.1109/LAWP.2015.2476515 · 1.58 Impact Factor
  • S. Ahdi Rezaeieh · A. Zamani · A. M. Abbosh
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    ABSTRACT: A 3-D slot-rotated antenna for a microwave head- imaging system is presented. The antenna is designed to have a wideband and unidirectional performance at the low microwave frequency band that are the requirements of the specified imaging system. Starting from a traditional wide-slot antenna, several conventional techniques are applied to enhance its bandwidth and directivity while miniaturizing its size. In that regard, four series of staircase-shaped slots are applied to lower the operating frequency, whereas a folding process is used to enhance the directivity and reduce the overall size. In addition, two parasitic patches are connected to the slot area to increase the operating bandwidth. The final design has the dimensions of 0.11 λ×0.23 λ×0.05 λ. ( λ is the wavelength of the lowest measured operating frequency.) It has a measured VSWR fractional bandwidth of 87% (1.41-3.57 GHz) and a peak front-to-back ratio of 9 dB. To verify the suitability of the antenna in head imaging, it is connected to a wideband microwave transceiver and used to circularly scan an artificial head phantom in 20° angle steps in a monostatic mode. The collected backscattered data are then processed and used to generate an image that successfully shows brain tumors. The compact size, wide operating bandwidth, unidirectional radiation, and detection viability are merits of the presented antenna and the subsequent system.
    IEEE Antennas and Wireless Propagation Letters 01/2015; 14:910-914. DOI:10.1109/LAWP.2014.2386852 · 1.58 Impact Factor

Publication Stats

2k Citations
158.62 Total Impact Points


  • 2005–2015
    • 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