| Summary: | 碩士 === 華梵大學 === 電子工程學系碩士班 === 95 === Among the wireless communication circuits, the spiral inductor is
play an important elements in radio frequency integrated circuits (RFICs).
Improvement of the quality factor (Q-factor) of inductors is important issue.
Since the Q-factor is the main determine that the loss of the metal strip and
substrate, much research has been devoted to improve the Q-factor by
reducing the metal or substrate loss.
In this work, by reducing the metal loss improved the Q-factor.We will
make use of an analytical formula is developed to efficiently determine
the line width in the variable line-width inductor design. the formula can
characterized by an equivalent series resistance Rs, an analytical formula
expression of the series resistance for a spiral inductor is first derived.
Nevertheless, Rs can be decomposed into the ohmic resistance Rohm and
the eddy-current resistance Reddy. By minimizing Rs, an analytical formula
for determining the proper line width (Wopt) of the n-th coil is then
formulated.
One method approach is the variable line width layout design. this
technique modifies a conventional spiral inductor with fixed line width that
is decreasing from the outer to the inner turns. By narrowing the width of
the inner coils, can be alleviated the loss due to induced current by the
time-varying magnetic flux passing through the metal lines in the inner
coils. Although this technique is effective and can be easily implemented
Q-factor by original technologies, it is generally difficult to find the proper
line width of each metal coil.
With the obtained analytical formula, the variable line width design
can be a very efficient and user-friendly method for improving the inductor
performance. We have been make use of several spiral inductors tested,by
EM numerical and measurement shows that the conspicuous can improve
Q-factor .
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