New techniques to design performance improved power dividers and directional couplers using the new scattering parameter relations
Author
Taş, Vahdettin
Advisor
Atalar, Abdullah
Date
2015Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Show full item recordAbstract
Wide bandwidth provides with several benefits in RF applications such as enabling
high data rates for communication applications, enhancing the multi
tread avoiding capabilities of the jamming systems, improving the effectiveness
of spread spectrum techniques. Operation in a wide bandwidth requires either
broadband components or multiple narrow band components together with sophisticated
multiplexing methods. There are several trivial methods to increase
the bandwidth of the RF components. For instance the bandwidth of a power
divider can be increased by increasing the number of sections which directly
increases the insertion loss and circuit size, burdening a big trade off for the
designer. The methods avoiding such a trade off are life savers in most of the
applications. Such methods require new design approaches. This work aims to
develop such methods with a special focus on improving the bandwidth and performance
of the power dividers and directional couplers. We derive new scattering
parameter relations and show that the relations require tricky design guidelines.
S-parameter relations for a number of power divider types and directional coupler
schemes are investigated. The derived equations have significant usages. One of
the equations is used to design the optimal isolation network for the Wilkinson
power divider. A number of equations imply a reduction in the number of the
optimization parameters in the design of n-section or n-way dividers. Another
equation is used to increase the directivity of microstrip directional couplers in
a wide bandwidth. Experimental results are presented verifying the theoretical
work.
Keywords
Scattering parametershigh directivity
coupling isolation phase difference
coupler phase relations
reflection coefficients
odd mode
even mode
isolation network
wideband power divider
Wilkinson divider