| Summary: | 碩士 === 國立臺北大學 === 通訊工程研究所 === 103 === This study presents the plane type triplexer. It is mainly designed at 1.2/1.9/2.75 GHz. This triplexer is applied on commercial set-top box (STB). We divide signal by triplexer after receiving RF signal by antenna. We capture signal which is in the frequency band we need, then downgrade the frequency to back-end to do signal process. It’s an important part in whole system and the isolation of each two bands is important too. The triplexer has one common port and three output ports. Using FR-4 printed circuit board(PCB) to fabricate triplexer. The size is 47.5mm × 23mm and thickness is 0.8mm. The research divides into two parts.
The first part is circuit design and confirming filter structure. We try and analyze the common filter types: Butterworth and Chebyshev. Finally, we choose Chebyshev type II as the main structure. Because it has a flatter pass band and better group delay. Based on a traditional band pass filter model, we transform a high pass filter series a low pass filter. We design and simulate the three different band’s BPFs in this way.
The second part is PCB layout, circuit tuning and implement result. We used layout software “P-CAD2006” to do PCB layout.
This study presents the plane type triplexer. The simulated results and measurement of the filters are not similar. We propose a better way to improve and fabricate it.
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