| Summary: | 碩士 === 國立成功大學 === 電機工程研究所 === 81 === Filter is one of the important devices in micro wave circuits.
Traditionally, the volume of the microwave filter is large.
However, dielectric cer amics filter has the advantages of high
dielectric constant, high Q value, compact in size,good tempe
rature stability,and low cost,it has already been widely used
in the mobile communicaion system. Dielectric ceramics filters
investigated in th iswork areconsisted of several cascaded
resonators propagating in TEM mode.The electromagnetic energy
istransmitted through air hole between neighboring resonators.
The filter response can becontrolled by adjusting the dimension
of the air holes. In this work, filters with different
features w ere studied.The one that can best fit the require
ment o the mobile communicationsystem at the frequ enciesfrom
800 MHz to900 MHz was found to have the features:central
frequency f=819.5MHz,S=-31.135dB, S=-2.1783 dB, Bandwidth=25MHz,
stopband loss at 750 MHz > 50dB.The dimension ofthe filter was
designed to be 24 mm *8 mm*10 mm.
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