الفهرس 
INTRODUCTION TO UWB SYSTEMSOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
With the advent of the information era, numerous advanced communication
technologies have arisen during the past two decades, which, have greatly influenced
and benefited every field of human society. With the need for increasing the data rate
of wireless systems, the ultra wideband (UWB) technology seems to be an ideal
candidate for future radio communication systems in various types of networks.
UWB technology has been swiftly evolving as one of the most promising
wireless technologies that provide the high bandwidth required by the latest and future
portable home and office devices for multiple digital video and audio streams. UWB
technology has been applied in many areas such as radar, remote sensing and military
and entertainment communications.
Microstrip patch antennas (MPAs) are widely used in the microwave frequency
region because of their simplicity and compatibility with printed-circuit technology
and ICs, making them easy to manufacture either as stand-alone elements or arrays.
In this thesis, probe fed rectangular microstrip patch antennas are investigated
to meet UWB requirements. The effect of patch dimensions, patch shape, dielectric
material, dielectric height, probe radius, and probe position on the operating
impedance bandwidth is investigated. Time domain characteristics are also
investigated to meet the required characteristics.
New eight UWB probe fed rectangular MPAs are introduced and all meet the
required UWB characteristics. A combination of multiple techniques is used to widen
the operating impedance bandwidth. Substrate superstrate technique is also used to
improve the operating impedance bandwidth. The peak gain and radiation efficiency
are simultaneously improved. Also the antenna group delay is greatly improved.
FEM via HFSS is used to simulate the proposed antenna structures. Also a
MATLAB program based on FDTD method is prepared and tested to verify the
characteristics of the proposed UWB MPAs. FIT via CST MWS is sometimes used to
verify the introduced structures when FDTD needs large computational time and
memory.