A Tunable Bandpass Filter With Modified Parallel-Coupled Line

Author

Ching-Wen Tang ; Chien-Tai Tseng ; Shih-Chieh Chang

Author_Institution

Dept. of Commun. Eng., Nat. Chung Cheng Univ., Chiayi, Taiwan

Volume

23

Issue

4

fYear

2013

fDate

Apr-13

Firstpage

190

Lastpage

192

Abstract

A tunable bandpass filter with a wide tuning range is presented in this letter. The proposed filter is composed of two modified parallel-coupled lines and one varactor-loaded stub. Particularly, the modified parallel-coupled line is realized by a varactor connected to one end of the coupled line with asymmetric feeding and an open stub added to the coupled line´s other end. Moreover, the varactor-loaded stub is introduced to control the transmission zero around the lower/higher passband skirt. The measured results show that a broad tuning range of 41.7%, from 0.95 to 1.45 GHz, was achieved. Within the tuning range, the insertion loss is from 2.4 to 2.9 dB and the return loss is greater than 15 dB.

Keywords

band-pass filters; coupled transmission lines; varactors; frequency 0.95 GHz to 1.45 GHz; loss 2.4 dB to 2.9 dB; modified parallel-coupled line; transmission zero; tunable bandpass filter; varactor-loaded stub; Band pass filters; Capacitance; Filtering theory; Loss measurement; Passband; Tuning; Varactors; Bandpass filter (BPF); tunable filter; varactor;

fLanguage

English

Journal_Title

Microwave and Wireless Components Letters, IEEE

Publisher

ieee

ISSN

1531-1309

Type

jour

DOI

10.1109/LMWC.2013.2247585

Filename

6473847