| Summary: | 碩士 === 國立臺北科技大學 === 電腦與通訊研究所 === 94 === This thesis is to extract increase the isolation of active circulators. First, to introduce the theory of active circulators include quasi circulators, and produce them
by active and passive circuits. The insertion loss of active circulators is to expect minimum. To observe the isolation of active circulators, find out the reasons the
isolation is low and its bandwidth is too narrow and modify the characteristic by many experiments. Passive circuits are made by microstrip lines, and active circuits
are consists of SGA-8343. The unbalanced amplitude of two signals used phase cancellation could be expected By VB programs. After VB programs computed, the attenuation of the two signals is known. Then, using multiple active or quasi circulators the new architecture increase the isolation will be found out. By comparing the isolation of single and multiple architecture, the feasibility of multiple architecture in MMIC technology will be expect.
In the other hand, bandpass and bandstop filters will be design by microstrip lines, and its insertion loss is about 3dB. A diplexer will be consisted of different type filters. By the design procedures of active circulator and diplexer, the isolation of different transmitting and receiving modes, using single frequency and dual frequencies, will be discussed.
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