Certain investigations on planar uwb antenna design for microwave imaging breast cancer detection

Abstract

In recent years, the number of cancer patients is increasing worldwide. Breast cancer is one of the most widely identified diseases among young age women. There are various methodologies for screening breast cancer. Mammogram is the commonly used method in which the human breast is compressed by the machine while taking the X-ray mammography images. The patient has to tolerate the pain until the screening gets completed. Ultrasound scanning device is used to transmit the high-frequency ultrasound waves on the human breast to identify the abnormality by converting it into the images. The recently utilized high-end screening methodology is Magnetic Resonance Imaging (MRI) scan. Even though the MRI scanning is more advanced than the mammogram, sometimes it results in false positive. These false positive findings of the patients lead to unneeded biopsies. This problem can be minimized by clearly distinguishing between the normal and malignant tissues of patients using Microwave Imaging (MWI). MWI is the non-invasive technique which differentiates the properties of tissues by the principle of scattering. It can detect the cancer tissue at a very earlier stage than the existing techniques. The Ultra-WideBand (UWB) antenna has high bandwidth spectrum; it offers a high resolution to detect the relatively small tumor. The antennas in the MWI systems act as sensors for transmitting UWB pulses and receiving the scattered waves from the human tissue. Hence the design of UWB antenna with compact size, high gain and directive radiation characteristics is a primary concern in MWI system. In the present research, design of UWB antenna categorized with two feeding mechanisms like microstrip line feed and Coplanar Waveguide (CPW) feed.The first section of the research involves the design of a Staircase monopole antenna with microstrip line feed for improved bandwidth and high gain. The etching of staircase steps at the bottom and the top of the rectangular patch antenna improve the impedance matching both at lower and at high frequencies. The implementation of the slots at the top of the patch and the ground plane leads to an improved bandwidth ratio of 5.875: 1. The overall size of the proposed antenna is 72 x 63 x 1.588 mm3 , and it has multiple resonances at 2GHz, 4 GHz, 5.8GHz and 7.4 GHz. A fractional bandwidth of 141% is achieved for the return loss of less than -10 dB. The antenna accomplishes a gain of 5.87 dBi. However, the bandwidth achieved by the proposed antenna is not sufficient and the size of the antenna also is large for cancer detection. Hence new designs in antenna are to be evolved to increase the bandwidth and to reduce the size of the antenna. newline