Design of microstrip bandpass filters with a dual-passband response

Author

Kuo, Jen-Tsai ; Yeh, Tsung-Hsun ; Yeh, Chun-Cheng

Author_Institution

Dept. of Commun. Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan

Volume

53

Issue

4

fYear

2005

fDate

4/1/2005 12:00:00 AM

Firstpage

1331

Lastpage

1337

Abstract

This paper presents a rigorous design of microstrip bandpass filters with a dual-passband response in parallel-coupled and vertical-stacked configurations. Based on resonance characteristics of a stepped impedance resonator (SIR), the second resonant frequency can be tuned over a wide range by adjusting its structure parameters. Emphasis is placed on filter synthesis for simultaneously matching in-band response and singly loaded Q by using tapped input/output couplings for the two designated passbands. Fractional bandwidth design graphs are used to determine proper geometric parameters of each coupled stage when filter specification is given. Realizable fractional bandwidths of the two passbands for a coupled SIR structure are clearly depicted in fractional bandwidth design graphs. Several experimental filters are fabricated and measured to demonstrate the design.

Keywords

band-pass filters; microstrip filters; resonators; dual-passband response; filter specification; filter synthesis; fractional bandwidth design graphs; in-band response matching; microstrip bandpass filters; parallel-coupled configuration; planar microwave filters; stepped impedance resonator; structure parameters; tapped input/output couplings; vertical-stacked configuration; Band pass filters; Bandwidth; Dual band; Frequency; Impedance; Microstrip filters; Microwave filters; Passband; Resonance; Resonator filters; Dual-passband; microstrip circuit; planar microwave filters; stepped impedance resonator (SIR);

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2005.845765

Filename

1420764