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Yifan Wang

Bio: Yifan Wang is an academic researcher from University of Queensland. The author has contributed to research in topics: Antenna (radio) & Microwave imaging. The author has an hindex of 13, co-authored 56 publications receiving 614 citations.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a portable microwave system to detect traumatic brain injuries is described, which utilizes a unidirectional antenna, microwave transceiver, and processing and image reconstruction algorithms, and a realistic head phantom, which attains accurate internal and external anatomical structure and electrical properties, is fabricated by a 3D printer using a detailed numerical model.
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.

175 citations

Journal ArticleDOI
TL;DR: In this article, double microstrip-slot transitions for planar ± 90° phase shifters are described and compared with a suitably chosen section of the microstripline, and the observed differential phase shift is accompanied by return losses of not less than 14 dB and insertion losses between 0.7 to 1.8 dB in the frequency band of 3.1-11.0 GHz.
Abstract: The letter describes double microstrip-slot transitions for use in planar ± 90° 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 ± 90° ± 7° 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 ± 90° ± 8° 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.

50 citations

Journal ArticleDOI
TL;DR: A synthetic bandwidth radar as an approach to build ultra-wideband (UWB) imaging systems is presented and is tested on breast imaging using the band 3-10 GHz via simulations and measurements on a realistic heterogeneous phantom.
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.

42 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe a wideband microstrip 180° hybrid, which makes use of two sides of a single-layer substrate and is formed by the out-of-phase and in-phase dividers which are suitably unified.
Abstract: The letter describes the design of a wideband microstrip 180° hybrid, which makes use of two sides of a single-layer substrate. The device is formed by the out-of-phase and in-phase dividers which are suitably unified. By making use of ground slots and microstrip to slot transitions all four its ports are of microstrip type. The hybrid exhibits a well-balanced power division between the output ports and good quality return losses of the out-of-phase (difference) and in-phase (summation) ports across the band from 3 to 9 GHz. The isolation between the output ports is better than 10 dB. The isolation between the difference and summation ports is greater than 40 dB and the phase characteristics are close to the ideal 180° and 0°.

36 citations

Journal ArticleDOI
TL;DR: In this paper, the design of a novel wideband microwave crossover is presented, which is fully compatible with microstrip circuits as it is printed on one side of a single-layer substrate.
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).

36 citations


Cited by
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Journal ArticleDOI
TL;DR: A wideband microwave system for head imaging that includes an array of 16 corrugated tapered slot antennas that are installed on an adjustable platform to detect brain injuries and to accurately detect the presence and location of the stroke is presented.
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.

309 citations

Journal ArticleDOI
05 Jul 2017-Sensors
TL;DR: An overview on recent important achievements in breast screening methods and breast biomarkers along with biosensors for rapidly diagnosing breast cancer along with microwave imaging techniques is provided.
Abstract: Early-stage cancer detection could reduce breast cancer death rates significantly in the long-term. The most critical point for best prognosis is to identify early-stage cancer cells. Investigators have studied many breast diagnostic approaches, including mammography, magnetic resonance imaging, ultrasound, computerized tomography, positron emission tomography and biopsy. However, these techniques have some limitations such as being expensive, time consuming and not suitable for young women. Developing a high-sensitive and rapid early-stage breast cancer diagnostic method is urgent. In recent years, investigators have paid their attention in the development of biosensors to detect breast cancer using different biomarkers. Apart from biosensors and biomarkers, microwave imaging techniques have also been intensely studied as a promising diagnostic tool for rapid and cost-effective early-stage breast cancer detection. This paper aims to provide an overview on recent important achievements in breast screening methods (particularly on microwave imaging) and breast biomarkers along with biosensors for rapidly diagnosing breast cancer.

233 citations

Journal ArticleDOI
TL;DR: In this paper, a portable microwave system to detect traumatic brain injuries is described, which utilizes a unidirectional antenna, microwave transceiver, and processing and image reconstruction algorithms, and a realistic head phantom, which attains accurate internal and external anatomical structure and electrical properties, is fabricated by a 3D printer using a detailed numerical model.
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.

175 citations

Journal ArticleDOI
TL;DR: In this paper, a 4-port multiple-input-multiple-output (MIMO) antenna array operating in the mm-wave band for 5G applications is presented, where an identical two-element array excited by the feed network based on a T-junction power combiner/divider is introduced, while the ground plane is made defected with rectangular, circular and a zigzag-shaped slotted structure to enhance the radiation characteristics of the antenna.
Abstract: We present a 4-port Multiple-Input-Multiple-Output (MIMO) antenna array operating in the mm-wave band for 5G applications. An identical two-element array excited by the feed network based on a T-junction power combiner/divider is introduced in the reported paper. The array elements are rectangular-shaped slotted patch antennas, while the ground plane is made defected with rectangular, circular, and a zigzag-shaped slotted structure to enhance the radiation characteristics of the antenna. To validate the performance, the MIMO structure is fabricated and measured. The simulated and measured results are in good coherence. The proposed structure can operate in a 25.5–29.6 GHz frequency band supporting the impending mm-wave 5G applications. Moreover, the peak gain attained for the operating frequency band is 8.3 dBi. Additionally, to obtain high isolation between antenna elements, the polarization diversity is employed between the adjacent radiators, resulting in a low Envelope Correlation Coefficient (ECC). Other MIMO performance metrics such as the Channel Capacity Loss (CCL), Mean Effective Gain (MEG), and Diversity gain (DG) of the proposed structure are analyzed, and the results indicate the suitability of the design as a potential contender for imminent mm-wave 5G MIMO applications.

156 citations

Journal ArticleDOI
TL;DR: In this paper, a planar ultrawideband modular antenna (PUMA) array is proposed to mitigate low-frequency bandwidth-limiting loop modes and shift problematic common-mode resonances out-of-band.
Abstract: The theory, design, fabrication, and measurement of a new class of planar ultrawideband modular antenna (PUMA) arrays are presented. The proposed PUMA array class achieves twice the bandwidth (from 3:1 to 6:1) of the conventional shorted via-based PUMA without using an external matching network and while retaining convenient unbalanced feeding, manufacturing, and assembly characteristics. The chief enabling technical innovation hinges upon the reconfiguration of shorting vias into capacitively-loaded vias that simultaneously: 1) mitigate low-frequency bandwidth-limiting loop modes and 2) shift problematic common-mode resonances out-of-band. A simple theoretical model based on ridged waveguides is proposed that qualitatively and quantitatively explains this novel common-mode mitigation. An infinite array operating over 3.53–21.2 GHz (6:1) is designed to achieve active VSWR < {2, 2.5, 3.8} while scanning to {broadside, 45°, 60°}, respectively, without oversampling the aperture. D-plane cross-polarization is around {−15, −10} dB for {45°, 60°} scans with high efficiency, i.e., 0.5 dB co-polarized gain loss on average. A dual-polarized prototype 256-port (128 elements per polarization) array is fabricated and measured having good agreement with full-wave finite array simulations.

149 citations