Executive Summary : | Microwave imaging was initially developed for investigation and military purposes. Now it is routinely implemented in various emerging applications which include healthcare, security monitoring, through-wall radar, and non-destructive examinations. It has been a center of wide implementation due to its non-invasive evaluation, non-ionizing nature which is safe for human exposure, long wavelengths, and can penetrate through optically opaque objects. At microwave frequencies, the distinct phases of the electromagnetic wave can be easily controlled and detected and hence enabling numerous consistent imaging approaches. Recently materials with negative permittivity and permeability known as meta-materials or meta-surfaces are popular among researchers. These are artificially developed materials with distinct electromagnetic properties as compared to their constituents, frequently leading to a negative refractive index, permittivity, and permeability. These play an important role in decreasing the unwanted side lobes of the radiation pattern. This can transform a spherical electromagnetic wave into a planar electromagnetic wave and hence improving the efficiency of the system. Computational microwave imaging system aims to have a low software and hardware complexities and increases the rate of data acquisition.
This project will cover an integration of meta-surface design and computational microwave imaging for implementing a cost-effective, low profile, and prompt microwave imaging system. We will start the investigation through the literature survey and explain the operation and implementations of various meta-surface antenna materials proficient in generating distinct illumination patterns at microwave frequencies. Their positive and distinctive aspects will be explained and the most appropriate material will be chosen. Here, the distinct design of each element of the meta-surface antenna will determine the appropriate resonant frequency. This will create an order of spatially diverse illumination patterns based on the frequency in which it is excited. A numerical simulation will be presented, which will substantiate the operation of our proposed system in the computational microwave system. Further, a parametric analysis will be executed based on the various relevant parameters affecting the efficiency of the system through image and resolution quality, geometry, quality and density factor of the meta-surface, frequency bandwidth, and a number of samples. |