Highly Selective Balanced to Unbalanced Bandpass Filter

• Main Authors: Yao-Jia Guo, 郭曜嘉
• Other Authors: Janne-Wha Wu
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/51329564482664966705

碩士 === 國立中正大學 === 電機工程研究所 === 103 === This thesis focuses on the design of balun bandpass filter, used behind the antenna in. All the proposed circuits were fabricated by PCB FR4 process. This thesis focuses on the design of balun bandpass filter, used behind the antenna in receiver. All the proposed circuits were fabricated by PCB FR4 process. A bandpass filter integrated with a balun, called “balun bandpass filter”, decreases the out band noise and makes two signals equal in amplitude but out of phase at output. The insertion loss is related to reflection coefficient Γ3 of the port-3. In this study, another way is different from a traditional type to create a additional transmission zero by changingΓ3, is proposed to improving the out band suppression. The middle section of this circuit adapt a three section SIR, adjusting the frequency of even mode response which is created by symmetrical coupled lines. Then the three section SIR coordinates Γ3 to change the frequency response and makes with good out band suppression performance. This work successfully implemented a passband from 2.43GHz to 2.53GHz, and a 25dB rejection upper stopband from 1.2f0 to 4.5f0.