الفهرس Only 14 pages are availabe for public view
 |  | from | 200 |  |  |
| | | from | 200 | | |
Abstract
In this thesis four proposed sensors for landmines detection have been investigated. The FDTD simulation is used to simulate the whole problem of landmines detection. The first proposed sensor consists of two rectangular microstrip patch antennas fabricated on the same substrate and ground plane. The first patch is considerd as the transimitter (TX) while the second patch is considered as the reciever (RX). The mutual coupling |S21| factor between the two patches is used to determine the presence of buried targets. The sensor has been used to detect different types of targets buried into different types of soil properties. The second proposed sensor consists of two rectangular microstrip patch antennas fabricated on the same substrate and ground plane and provided with shoring pins between the patch and ground plane. The compensated sensor is designed to detect different types of targets buried into different types of soil properties. The calculated results show that the compensated sensor has more detection capability compared to the first proposed sensor. The third proposed sensor consists of two rectangular microstrip patch antennas with corrugated ground between the two microstrip patch antennas. The corrugated ground structure has reduced the mutual coupling between the two microstrip patch antennas. The calculated results show that the sensor with corrugated ground plane has more detection capability for detecting some targets buried into various types of soil properties compared to the classical senor without corrugated ground. The fourth proposed sensor consists of two rectangular microstrip elements fabricated on the same ground plane but with a defected ground structure in the
backside of the antenna at the middle between the two patches. The defects in the ground plane have the advantages of reducing the coupling between the two Abstract patches at the resonance frequency compared to the classical antenna with smooth ground plane. The calculated results show that the sensor with defected ground plane has more detection capability for detecting some targets buried into various types of soil properties compared to the classical senor without defected ground plane.
The effects of varying the shape of the ground surface as well as the electrical
permittivity have affected the detection process. The reflected signals from the
ground surface are varying from the case of soil with smooth ground surface to
rough surface. The intensity and direction of the reflection depend on two
factors: the roughness of the surface and the electric property of the medium.
The FDTD method is used to simulate the whole problem of landmine
detections which includes the two microstrip element antennas, the microstrip
antenna feed, the earth properties and the buried objects properties. The
calculated results are verified using the FIT (finite integration Technique)
method.
The obtained results show that the landmines detection process is based on the
type of the sensor, the soil electrical properties, the target electrical properties,
sensor height and target depth.