الفهرس 
صفحة العنوانيوجد فقط 14 صفحة متاحة للعرض العام
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المستخلص
The development of Ultra Wide Band (UWB) technology, including antennas as
an essential part of wireless communication systems, is greatly accelerated. However,
there are more challenges in designing a UWB antenna more than a narrow band one.
It should be capable of operating over an ultra-wide bandwidth as allocated by the
Federal Communications Commission (FCC) from 3.1 GHz to 10.6GHz. At the same
time, the radiation properties over the entire frequency range are also necessary to be
satisfactory. This thesis focuses on a designing a novel microstrip Ultra Wide Band
(UWB) antenna for optimum performance like wide bandwidth, good matching
impedance, small antenna size exhibits a good voltage standing wave ratio (VSWR)
performance and its E- and H-plane radiation patterns are stable over the UWB
frequency range and others. This antenna has a new patch shape that allows for
providing good properties. Discussing the necessary parameters of UWB antennas, and
studying the techniques of enhancing the bandwidth of a microstrip UWB are also
investigated, to get antenna exhibit excellent performance of UWB characteristics with
enhanced bandwidth.
The first antenna, a novel ultra-wideband microstrip slot antenna with
frequency notched function is proposed. The antenna is similar to conventionally
printed slot antennas, but a fractal tuning stub has been employed to achieve
frequency notched function. The operation bandwidth of the antenna is from 3.1 to
10.6 GHz, in which a frequency notched band from 5 to 6 GHz has been achieved,
and relative omni-directional and stable radiation patterns over the entire
frequency range have also been achieved. The first antenna studied in this thesis is
Stepped-Trapezoidal Notched UWB Aritenna for Wireless Communications which is
fed by son microstrip line. Initial, the substrate is selected to be Rogers RTlDuroid
5880 material with a relative permittivity £[=2.2 and a thickness of 1.575 mm. Second,
the radiator shape is chosen to be trapezoidal ago it can show a UWB characteristic.