Filter Designs with Harmonic Suppression Using Transmission Zeros from Coupling Structures

• Main Authors: Chih-HsuanLiu, 劉稚暄
• Other Authors: Chih-Ming Tsai
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/t9583j

碩士 === 國立成功大學 === 電腦與通信工程研究所 === 105 === In this thesis, we studied the harmonic-suppressed bandpass filter is based on discriminating coupling proposed by X. Y. Zheng and Q. Xue. Discriminating coupling is used to obtain zero coupling coefficient at high order harmonic. Then we provides a different way of deriving the equivalent circuit of the discriminating coupling structure by using Sato’s network model of coupled transmission lines. To increase the freedom of filter design we analysis of four types of coupled-line structures: coupled lines with load at one end. The equation for the transmission zero of coupled lines with load at one end has been derived from its network model. Based on this equation, coupled lines with different loads at one end are analyzed and the rules for controlling the transmission-zero frequency are given. Finally, two case of band-pass filters are designed, and verify the practicability through EM simulation.The last part of this thesis we studied the tuning method of coupled-resonator filters by John B. Ness. Furthermore, we discuss the problem of tuning band-pass filter network fabricated on microstrip line structures.