OPTIMIZATION OF TWI SYSTEM FOR MIMO BASED CON_GURATION

Abstract

The dissertation report is focused towards the study of ThroughWall Imaging (TWI) System for Multiple Input Multiple Output (MIMO) based con guration in Ultra Wide Band (UWB) range of 1.7 3.3 GHz and its optimization. For penetrating the wall, the transmitted signal must be of low frequency with wider bandwidth for greater resolution. So, a signal centered at 2.5 GHz frequency with a bandwidth of 1.6 GHz meets the conditions of better penetration and high resolution. The e ects of antenna element spacing, frequency band, and target Radar Cross Section are quanti ed. Furthermore, the degree of decorrelation that antennas typical of a tactical missile environment may achieve is quanti ed. The results show that a signi cant degree of decorrelation may be achieved for a speci c class of targets and certain frequency bands even with small antennas. The objective of TWI systems is to spot the position and motion of humans or stu s, located behind the wall. Relative bandwidth of the system is 0.64 and therefore it meets the criteria of relative bandwidth greater than 0.2 set by Federal Commission Communication for UWB system. Various research papers were studied on the subject of MIMO based TWI system and based upon those multiple simulations were carried out. Comprehensive study for the parametric analysis of spatial diversity on di erent MIMO con gurations and simulation for both monostatic contiguous virtual array and of contiguous virtual array with independent transmitter and receiver were done. Finally, parametric analysis for spatial diversity of Antenna with various MIMO con guration was simulated. Antenna array with Vivaldi elements is con gured and various parameters such as S-parameters, Pattern Analysis, Total Active Re ection Coe cient (TARC), Envelope Correlation Coe cient (ECC) etc. were computed using MATLAB simulation tool and all the results are explained. Back-projection algorithm was also studied and simulated. Methodologies were also developed for proper and accurate simulations of systems with di erent MIMO con guration.