الفهرس 
History of UWB Technology
MotivationOnly 14 pages are availabe for public view
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Abstract
Ultra-wideband (UWB) applications have captured attention as a high-speed secured wireless
communications with extremely low power consumption. There are many challenges when
dealing with these new applications. One of them is how to design a power divider (PD) that can
perform effectively in the entire UWB frequency range from 3.1 GHz to 10.6 GHz. This thesis
mainly focused on designing power dividers for UWB systems. The performance criteria of power
divider such as insertion loss, output ports isolations and return loss are discussed as well as PD
different design methodologies and technologies. Different techniques to enhance the
performance of power divider are investigated and tested, such as bandwidth broadening, isolation
enhancement and matching improvement.
A novel N-way power divider design for UWB systems is developed. The design is realized using
two cascaded sections of Wilkinson PD of equal characteristic impedances and unequal electrical
lengths with inserted open stub on each section to enhance the isolation, matching and to broaden
the bandwidth. The analytical solution for the designed N-way power dividers is based on two
approaches namely “Even-Odd Mode Method” and the “ABCD Matrix” Method. Simple design
equations and guidelines are proposed to facilitate the design procedure and limit the usage of
CAD simulators and optimizers. To verify the proposed design methodology, 2-way, 3-way and
4-way PD for UWB are designed, simulated and implemented.
The 2-way power divider for UWB systems is tested using EM-Circuit Co-Simulation then
fabricated, measured and compared with similar published PD. It has an isolation of better than
13.5 dB within the entire UWB frequency band and has a compact area of 22 * 15 mm2.
Measurement and simulation results agrees well, which verifies the proposed design equations as
well as the design procedure. In addition, the proposed circuit is compared to conventional
published ones to show the enhancement percentage in different performance parameters, where
the 2-way proposed circuit achieves 23% isolation enhancement and better than 45 % of return
loss enhancement. The 3-way and 4-way power dividers design equations are introduced along
with the suggested planar microstrip implementation. Another 4-way power divider is proposed
using three 2-way PD. This method is more realistic in planar microstrip fabrication. This
proposed 4-way PD is fabricated, measured and compared to published available ones. It has an
isolation of better than 12.5 dB and a return loss of better than 10 dB through the whole UWB
range. Furthermore, the exceeded insertion loss is less than 1.8 dB and the occupied area is 40*34
mm2. Finally, the proposed structures as well as the developed design procedure are very useful
for UWB applications.