Globally, breast cancer is a major reason for female mortality. Due to the limitations of current clinical imaging, the researchers are encouraged to explore alternative and complementary tools to available techniques to detect the breast tumor in an earlier stage. This article outlines a new, portable, and low-cost microwave imaging (MWI) system using an iterative enhancing technique for breast imaging. A compact side slotted tapered slot antenna is designed for microwave imaging. The radiating fins of tapered slot antenna are modified by etching nine rectangular side slots. The irregular slots on the radiating fins enhance the electrical length as well as produce strong directive radiation due to the suppression of induced surface currents that radiate vertically at the outer edges of the radiating arms with end-fire direction. It has remarkable effects on efficiency and gain. With the addition of slots, the side-lobe levels are reduced, the gain of the main-lobe is increased and corrects the squint effects simultaneously, thus improving the characteristics of the radiation. For experimental validation, a heterogeneous breast phantom was developed that contains dielectric properties identical to real breast tissues with the inclusion of tumors. An alternative PC controlled and microcontroller-based mechanical MWI system is designed and developed to collect the antenna scattering signal. The radiated backscattered signals from the targeted area of the human body are analyzed to reveal the changes in dielectric properties in tissues. The dielectric constants of tumorous cells are higher than that of normal tissues due to their higher water content. The remarkable deviation of the scattered field is processed by using newly proposed Iteratively Corrected Delay and Sum (IC-DAS) algorithm and the reconstruction of the image of the phantom interior is done. The developed UWB (Ultra-Wideband) antenna based MWI has been able to perform the detection of tumorous cells in breast phantom that can pave the way to saving lives.

A novel, low cost, and comprehensive microwave imaging (MWI) system is presented for the detection of unwanted tumorous cells into the human breast. A compact metamaterials (MTM) artificial magnetic conductor (AMC) surface-inspired coplanar waveguide fed (CPW-fed) microstrip antenna is developed for MWI applications. The initial wideband CPW antenna is designed by the modified oval shape patch and half cycle copper stripe line ground. The antenna is incorporated with two layers uniplanar AMC structure which is composed of a $5\times 5$ array of square modified split ring resonator unit cells to obtain the desired antenna characteristics for the MWI applications like breast imaging. The metamaterial-based AMC structure improves the gain about 5 dB and produces stronger directive radiation characteristics. The enhancement of CPW performance proofs the effectiveness of the double layer MTM-AMC structure and its suitability for MWI. A microcontroller-based PC controlled alternative mechanical imaging system is designed to collect the scattering signal from the CPW-fed antenna. The changes of reflection and transmission coefficient with the variation of dielectric content into the breast phantom structure are analyzed. The remarkable deviation of scattered field is processed by image processing program using Matlab. By using these AMC inspired CPW-fed antenna based microwave imaging, the system can clearly detect the tumor inside the breast phantom.

In this paper, a system for microwave breast tumor detection is presented using iteratively corrected coherence factor delay and sum (CF-DAS) algorithm. CF-DAS is data independent, which makes it stable in a noisy environment. However, data adaptive techniques have made significant progress by enhancing the image quality in microwave tomography. Thus, a novel data adaptive iterative variant of CF-DAS is proposed in this paper to produce stable and accurate images. The microwave imaging (MI) system contains a rotatable array of nine modified antipodal Vivaldi antennas in a circular arrangement, an array-mounting stand based on the stepper motor, the flexible phantom mounting podium, a control system for RF switching of the transceivers, and signal processing unit based on personal computer involved in the reconstruction of the image. The impedance bandwidth of the modified antenna is recorded from 2.5 to 11 GHz with stable directional radiation pattern. For performing the transmission and reception of the microwave signals, an SP8T nine port RF switch is used ranging from 2.5 to 8.0 GHz, and the switching is controlled by MATLAB software. Several low-cost lab-based homogenous and heterogeneous phantoms containing the dielectric property of human breast and tumor tissue are prepared to test the system efficiency. Since typical data independent radar-based techniques are ill-equipped for multiple reflection scenarios, an iteratively corrected variant of CF-DAS algorithm is used for processing the recorded backscattered signals to reconstruct the image of the breast phantom and to identify the existence and locate the area of the multiple breast tumors. The proposed method achieves more than 10-dB improvement over conventional CF-DAS in terms of signal to mean ratio for four different phantoms measured in this study.

In this paper, a new, complete, and comprehensive breast phantom measurement system is presented. A side slotted vivaldi antenna is used for breast phantom measurement. The radiating fins are modified by etching six side slots to enhance the electrical length and produce stronger directive radiation with higher gain. This approach reduces the lower operating frequency and increases the gain and efficiency without compromising the size of the antenna. The overall size of the antenna is 8.8 (L) × 7.5 (W) cm ² or approximately 0.4λ × 0.5λ at the first resonant frequency of 1.79 GHz. The results show that the antenna has a fractional bandwidth of approximately 127% from 1.54 to 7 GHz for return loss less than 10 dB with a directional radiation pattern. The average gain of the proposed prototype is 8.5 dBi, and the radiation efficiency is approximately 92% on average over the operating bandwidth. The fidelity factor for face to face is 0.98, and that for side by side is 0.4479, which proves the directionality and lower distortion of the signal. The prototype is successfully simulated, fabricated, and analyzed. The radiating fins of the proposed prototype are optimized to achieve the desired properties for breast phantom measurement. The antenna is used as the transceiver in a breast phantom measurement system to detect unwanted tumor cells inside the breast. An automated electromechanical imaging system with the necessary data post processing makes it an easy and suitable tool for microwave imaging to detect breast tumors.

A new, compact planar wideband negative index metamaterial based on a modified split ring resonator (SRR) is studied to enhance performance of ultrawideband antenna. A compact, metamaterial (MTM)-inspired microstrip antenna is presented for microwave imaging system (MIS) application. Two layers of left-handed metamaterial array (2 × 4) of the unit cell are placed on the radiating patch and the ground plane, respectively. Each left-handed metamaterial (LHM) unit cell was constructed by modifying a square split ring resonator (SRR), resulting in negative permeability and permittivity with a stable negative refractive index. The results shows that it has a significant impact on the performance of conventional patch antenna in terms of transmission co-efficient, efficiency and low loss. Compared to antenna without LHM, it is shown that the bandwidth is significantly broadened up to a few megahertz and becomes more convergent leading to the achievement of desired properties for ultra-wideband (UWB) applications leading to microwave imaging. The proposed MTM antenna structure is fabricated on commercially-available, flame-retardant material of size 26 × 22 × 1.6 mm³ with 4.6 dielectric constants, due to its low cost and convenience for making multilayer printed circuit boards (PCBs). The antenna achieves 3.1 GHz to 10.71 GHz of impedance bandwidth (−10 dB), which covers the full UWB band. The use of double-layer negative index MTM unit cells enhances UWB performance, and the improved radiation efficiency, nearly directional radiation pattern, acceptable gain, stable surface current and negative refractive index make this MTM antenna a suitable candidate for UWB applications.