Title :
Hairpin filters with tunable transmission zeros
Author :
Chih-Ming Tsai ; Sheng-Yuan Lee ; Chin-Chuan Tsai
Author_Institution :
Dept. of Electr. Eng., Nat. Cheng Kung Univ., Tainan, Taiwan
Abstract :
In the previous work, it was found that filter designed with 0/spl deg/ feed structure could have two extra transmission zeros in the stopband. In this paper, a method for tuning the frequencies of these two transmission zeros using impedance transformers is proposed. These zeros can be tuned to reject unwanted signals near the passband, such as image signals, This new approach has been experimentally verified with three second-order Butterworth filters.
Keywords :
Butterworth filters; UHF filters; circuit tuning; passive filters; poles and zeros; resonator filters; feed structure; hairpin filters; image signal rejection; impedance transformers; second-order Butterworth filters; tunable transmission zeros; Equations; Feeds; Filtering theory; Frequency; Impedance; Passband; Resonator filters; Transformers; Transmission lines; Tunable circuits and devices;
Conference_Titel :
Microwave Symposium Digest, 2001 IEEE MTT-S International
Conference_Location :
Phoenix, AZ, USA
Print_ISBN :
0-7803-6538-0
DOI :
10.1109/MWSYM.2001.967346
