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Directional Wideband Wearable Antenna with Circular Parasitic Element for microwave imaging Applications

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Computers, Materials & Continua 2022年第7期72卷 983-998页

作者： N.A.Koma’rudin Z.Zakaria A.A.Althuwayb H.Lago H.Alsariera H.Nornikman A.J.A.Al-Gburi P.J.Soh Faculty of Electronic and Computer Engineering(FKEKK) Universiti Teknikal Malaysia Melaka(UTeM)Durian Tunggal76100MelakaMalaysia Electrical Engineering Department Jouf UniversitySakaka72388AljoufKingdom of Saudi Arabia Faculty of Engineering Universiti Malaysia Sabah(UMS)Kota Kinabalu88400SabahMalaysia Centre for Wireless Communications(CWC) University of OuluOulu90014Finland Advanced Communication Engineering(ACE)CoE Faculty of Electronic Engineering TechnologyUniversiti Malaysia Perlis(UniMAP)Arau02600PerlisMalaysia

This work proposes a wideband and unidirectional antenna consisting of dual layer of coplanar waveguide based on the circular parasitic element *** design procedure is implemented in three stages:Design A,which operates at 3.94 GHz with a bandwidth of 3.83 GHz and a fractional bandwidth(FBW)of 97.2%;Design B,which operates at 3.98 GHz with a bandwidth of 0.66 GHz(FBW of 56.53%);and Design C as the final *** final Design C is designed to resonate at several frequencies between 2.89 and 7.0 GHz for microwave imaging applications with a bandwidth of 4.11 GHz(79.8%)centered at 5.15 *** antenna is fabricated fully using two textile materials:felt as the substrate and ShieldIt as the *** features a unidirectional radiation with a gain of 5.5 dBi,and reduced lowback radiation from 2.06 to−7.81 *** front-to-back ratio(FBR)for Design A,Design B and Design C are 4.82,2.94 and 11.36 dB,*** antenna is wideband with unidirectional radiation,lightweight,and flexible.

关键词： Wearable antennas ultrawideband antennas unidirectional antennas microwave imaging

Recent Advances in Short-Range microwave imaging in Europe

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Advances in Manufacturing 1998年第1期2卷 4-17页

作者： Matteo Pastorino (Department of Biophysical and Electronic Engineering, University of Genova, Italy)

This paper reports the content of a lecture presented at the 1995 International Conference and Exhibition on Electronic Measurement and Instrumentation, held in Shanghai, China in 1995. The paper presents(thanks to the courtesy of several scientists) some of the most significant results recently obtained in the field of short range microwave imaging. The overview concerns the research activity carried out in Europe and is focused on microwave imaging for non destructive testing, civil engineering, and scientific and medical applications. This type of imaging is characterized by a relatively short distance between the object to be detected and the probes.

关键词： microwave imaging inverse scattering spectrum domain method space domain method

Near Field microwave Holography for Bio-Tissue imaging

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Open Journal of Medical imaging 2020年第3期10卷 143-150页

作者： Yoshihiko Kuwahara Kimihito Fujii Department of Electrical and Electronic Engineering Shizuoka University Hamamatsu Japan Division of Breast and Endocrine Surgery Department of Surgery Aichi Medical University Nagakute Japan

This study investigated the ability of microwave holography to accurately reconstruct the tissue structure of the human body. Numerical breast and head phantoms were imaged by 3D near-field holography using backscattered waves obtained by a monostatic planar scan. Complex organizational structures have been reconstructed accurately and quickly. In addition, breasts with relatively simple histology could be reconstructed without the matching liquid.

关键词： microwave imaging Near Field Holography Bio-Tissue

High-precision RCS measurement of aircraft's weak scattering source

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Chinese Journal of Aeronautics 2016年第3期29卷 772-778页

作者： Hu Chufeng Li Nanjing Chen Weijun Zhang Linxi Science and Technology on UAV Laboratory Northwestern Polytechnical University

The radar cross section （RCS） of weak scattering source on the surface of an aircraft is usually less than -40 dBsm. How to accurately measure the RCS characteristics of weak scattering source is a technical challenge for the aircraft＇s RCS measurement. This paper proposes separating and extracting the two-dimensional （2D） reflectivity distribution of the weak scattering source with the microwave imaging algorithm and spectral transform so as to enhance its measurement preci- sion. Firstly, we performed the 2D microwave imaging of the target and then used the 2D gating function to separate and extract the reflectivity distribution of the weak scattering source. Secondly, we carried out the spectral transform of the reflectivity distribution and eventually obtained the RCS of the weak scattering source through calibration. The prototype experimental results and their analysis show that the measurement method is effective. The experiments on an aircraft＇s low-scattering conformal antenna verify that the measurement method can eliminate the clutter on the surface of aircraft. The precision of measuring a -40 dBsm target is 3 5 dB better than the existing RCS measurement methods. The measurement method can more accurately obtain the weak scattering source＇s RCS characteristics.

关键词： microwave imaging RCS measurement Reftectivity distributionSpectral transform Weak scattering source

Analysis of Ice Water Path Retrieval Errors Over Tropical Ocean

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Advances in Atmospheric Sciences 2006年第2期23卷 165-180页

作者：黄建平 College of Atmospheric Sciences Lanzhou University Lanzhou 730000

Retrieval of multi-layered cloud properties, especially ice water path （IWP）, is one of the most perplexing problems in satellite cloud remote sensing. This paper develops a method for improving the IWP retrievals for ice-over-water overlapped cloud systems using Tropical Rainfall Measuring Mission （TRMM） microwave Imager （TMI） and Visible and Infrared Scanner （VIRS） data. A combined microwave, visible and infrared algorithm is used to identify overlapped clouds and estimate IWP separately from liquid water path. The retrieval error of IWP is then evaluated by comparing the IWP to that retrieved from single-layer ice clouds surrounding the observed overlapping systems. The major IWP retrieval errors of overlapped clouds are primarily controlled by the errors in estimating the visible optical depth. Optical depths are overestimated by about 10-40% due to the influence of the underlying cloud. For the ice-over-warm-water cloud systems （cloud water temperature Tw 〉 273 K）, the globally averaged IWP retrieval error is about 10%. This cloud type accounts for about 15% of all high-cloud overlapping cases. Ice-over-super-cooled water clouds are the predominant overlapped cloud system, accounting for 55% of the cases. Their global averaged error is -17.2%. The largest IWP retrieval error results when ice clouds occur over extremely super-cooled water clouds （Tw ≤ 255 K）. Overall, roughly 33% of the VIRS IWP retrievals are overestimated due to the effects of the liquid water clouds beneath the cirrus clouds. To improve the accuracy of the IWP retrievals, correction models are developed and applied to all three types of overlapped clouds. The preliminary results indicate that the correction models reduce part of the retrieval error.

关键词： Ice water path multi-layered cloud microwave imaging retrieval errors

Contour Detection-Based Realistic Finite-Difference-Time-Domain Models for microwave Breast Cancer Detection

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Transactions of Tianjin University 2016年第6期22卷 572-582页

作者：王梁肖夏宋航路红刘佩芳 School of Electronic Information Engineering Tianjin University Tianjin 300072 China Department of Radiology Tianjin Medical University Cancer Institute and Hospital Tianjin 300060 China

In this paper, a collection of three-dimensional(3D)numerical breast models are developed based on clinical magnetic resonance images(MRIs). A hybrid contour detection method is used to create the contour, and the internal space is filled with different breast tissues, with each corresponding to a specified interval of MRI pixel intensity. The developed models anatomically describe the complex tissue structure and dielectric properties in breasts. Besides, they are compatible with finite-difference-time-domain(FDTD)grid cells. Convolutional perfect matched layer(CPML)is applied in conjunction with FDTD to simulate the open boundary outside the model. In the test phase, microwave breast cancer detection simulations are performed in four models with varying radiographic densities. Then, confocal algorithm is utilized to reconstruct the tumor images. imaging results show that the tumor voxels can be recognized in every case, with 2 mm location error in two low density cases and 7 mm─8 mm location errors in two high density cases, demonstrating that the MRI-derived models can characterize the individual difference between patients' breasts.

关键词： 3D breast model contour detection finite-difference-time-domain(FDTD) convolutional perfectmatched layer(CPML) microwave imaging

Large Scale Analysis of Complex Permittivity of Breast Cancer in microwave Band

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Advances in Breast Cancer Research 2020年第4期9卷 101-109页

作者： Yoshihiko Kuwahara Akira Nozaki Kimihito Fujii Department of Electric and Electronical Engineering Faculty of Engineering Shizuoka University Hamamatsu Japan Division of Breast and Endocrine Surgery Department of Surgery Aichi Medical University Nagakute Japan

To obtain some prior knowledge of breast cancer detection by microwave imaging, we have measured and analyzed the complex permittivity of tissues extracted from over 140 breast cancer surgeries. The relative permittivity and conductivity of tumor at 1.6 GHz were 17.5% and 16.2% higher than those of mammary gland tissue, respectively. In invasive ductal carcinoma of scirrhous type, 8 out of 64 had higher relative permittivity and conductivity of mammary gland than those of tumor. However, when evaluated by the Debye parameter considering the frequency dependence of the tissue, it is rare that ε∞ and Δε of cancer are simultaneously lower than those of mammary gland. The relative permittivity and conductivity of fibroadenoma are almost the same as those of mammary glands. The relative permittivity and conductivity of each tissue showed strong linearity. Microwave imaging requires accurate reconstruction of ε∞ and Δε to distinguish cancer from normal tissue.

关键词： Breast Cancer Detection microwave imaging Complex Permittivity Debye Model

A brain stroke detection method based on deep learning method

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A brain stroke detection method based on deep learning metho...