Centre of Advanced Electronic and Communication Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.
Sensors (Basel). 2018 Dec 14;18(12):4427. doi: 10.3390/s18124427.
An experimental system for early screening of a breast tumor is presented in this article. The proposed microwave imaging (MI) system consists of a moveable array of nine improved negative-index metamaterial (MTM)-loaded ultrawideband (UWB) antenna sensor with incorporation of a corresponding SRR (split-ring resonator) and CLS (capacitively loaded strip) structure, in a circular array, the stepper motor-based array-mounting stand, the adjustable phantom hanging platform, an RF switching system to control the receivers, and a personal computer-based signal processing and image reconstruction unit using MATLAB. The improved antenna comprises of four-unit cells along one axis, where an individual unit cell integrates a balancing SRR and CLS pair, which makes the antenna radiation omnidirectional over the operating frequencies. The electrical dimensions of this proposed antenna are 0.28 × 0.20 × 0.016, measured at the lowest operating frequency of 2.97 GHz as the operating bandwidth of this is in between 2.97⁻15 GHz (134.82% bandwidth), with stable directional radiation pattern. SP8T 8 port switch is used to enable the eight receiver antennas to sequentially send a 3⁻8.0 GHz microwave signal to capture the backscattered signal by MATLAB software. A low-cost realistic homogeneous breast phantom with tumor material is developed and measured to test the capability of the imaging system to detect the breast tumors. A post-processing delay-multiply-and-sum (DMAS) algorithm is used to process the recorded backscatter signal to get an image of the breast phantom, and to accurately identify the existence and located area of multiple breast tumor tissues.
本文提出了一种用于早期乳腺癌筛查的实验系统。所提出的微波成像（MI）系统由一个可移动的九单元改进型负折射率超宽带（MTM）负载天线传感器阵列组成，其中包含相应的 SRR（分裂环谐振器）和 CLS（电容加载条）结构，呈圆形排列，基于步进电机的阵列安装架，可调节的仿体悬挂平台，用于控制接收器的射频开关系统以及基于 MATLAB 的个人计算机信号处理和图像重建单元。改进后的天线在一个轴上包含四个单元，其中单个单元集成了一对平衡的 SRR 和 CLS，这使得天线在工作频率上具有全向辐射特性。该天线的电气尺寸为 0.28×0.20×0.016，在最低工作频率 2.97GHz 处测量，其工作带宽在 2.97⁻15GHz 之间（带宽为 134.82%），具有稳定的定向辐射模式。SP8T 8 端口开关用于使八个接收天线依次发送 3⁻8.0GHz 微波信号，以便通过 MATLAB 软件捕获背散射信号。开发并测量了具有肿瘤材料的低成本真实均匀乳房仿体，以测试成像系统检测乳房肿瘤的能力。使用后处理延迟乘法求和（DMAS）算法处理记录的背散射信号，以获得乳房仿体的图像，并准确识别多个乳房肿瘤组织的存在和位置区域。
