A novel microwave subsurface diagnostic procedure for detection of defects inside coated dielectric structures using complementary split ring resonator (CSRR) based planar microwave sensor is presented. The sensor is made to scan the test structure and the shift in resonant frequency at the loaded and unloaded conditions are recorded at each scan point. Quantitative as well as qualitative microwave images of the test region are formed based on these variations. Mathematical model based on the shift in resonant frequency is also developed to retrieve the permittivity distribution of the dielectric test structure. Simulation and experimental results validate the usability of the designed sensor for practical imaging purposes.
In this paper, a 2.45 GHz harmonic suppression capability of array antenna has been presented for wireless power transfer applications. Harmonic suppression up to a fourth order of the fundamental operating frequency has been achieved by using rectangular slot Defected Ground Structure (DGS). The designed antenna uses an FR4 material having thickness 1.6 mm as a substrate which has loss tangent tanδ) 0.02. The gain and radiation efficiency are 4.5dB, 75% respectively. This antenna is suitable for rectenna applications.
A compact four-element 8-shaped self-affine fractal UWB MIMO antenna is presented. The self-affine fractal structure provides miniaturization and wideband characteristics to the antenna. The 8-shaped self-affine fractal geometry is designed up to the second iteration by iterated function system (IFS). This reduces the single-element antenna area by 24.88%. The dimension of proposed compact MIMO antenna is 44×44 mm2 and its impedance bandwidth ranges (S11 < −10 dB) from 3.1 GHz to 11 GHz. The mutual coupling is lesser than −16 dB across the entire operating frequency band. The correlation coefficient is less than 0.1 and diversity gain is more than 9.95 across the operating frequency band. Results of this antenna indicate that it is suitable for UWB applications.
Characteristics of silicon photonic integrated circuits that have enabled their inclusion in digitial communication systems are discussed. Frequencies and wavelengths of operation of microwave and optical/infrared systems of interest are defined. The uses of optical components in microwave systems are motivated and demonstrations of such microwave optical systems are reviewed. The literature that discusses silicon photonic devices for generation, shaping and processing of microwave signals is overviewed. Microwave photonic applications in which components developed for digital communication can serve as building blocks are discussed.
Polarimetrie Synthetic Aperture RADAR (SAR), is an emerging technology in the field of remote sensing today which has several applications in a number of study areas. It has a unique feature as it combines the enhanced resolution that is available through the use of SAR with the wave properties of Polarised electromagnetic energy caused due to scattering of radiation as it interacts with different features on earth's surface. A polarimetric backscatter signature is a three-dimensional saddle plot which is created when ellipticity, orientation angle and amplitude of the backscattered polarised wave is graphed. Since different features interact differently with the polarised wave, each man-made and natural feature causes a unique scattering of the polarised wave which is studied in the backscatter signature received. Based on different scattering mechanisms, a number of decomposition models were proposed like Freeman's decomposition model, Sinclair decomposition model, Pauli's decomposition, Yamaguchi's decomposition model and many more. Based on the relative scattering of the polarised wave, the identification and classification of various feature classes was possible. In this study it was aimed to study the different polarimetric decomposition models and the man-made and natural features detected in each, based on the relative scattering mechanisms and their relative classification using machine learning and object oriented approaches with improved classification accuracy.
