Design and application of microstrip parallelcoupled lines employing step-impedance transmission-line compensation

Author

Kumpang, S. ; Phromloungsri, Ravee ; Chongcheawchamnan, Mitchai ; Krairiksh, Monai ; Robertson, Ian D.

Author_Institution

Res. Center of Electromagn.-Wave Applic., Mahanakorn Univ. of Technol., Bangkok

Volume

3

Issue

3

fYear

2009

fDate

4/1/2009 12:00:00 AM

Firstpage

410

Lastpage

415

Abstract

The application of step-impedance transmission lines (SITLs) to improving the directivity of parallel-coupled microstrip lines is presented. A simple design procedure for two configurations based on the SITL technique is given. The application of the technique is demonstrated practically with a design at 0.9 GHz on an RF60 substrate. The directivities obtained from the measured results are improved by more than 6 and 30 dB compared with the designed uncompensated coupler. The compensation technique is then applied to the design of a coupled-line resonator and bandpass filter for suppressing harmonic responses in these circuits. Experimental results show that the second harmonic in the filter response is suppressed by 30 dB.

Keywords

band-pass filters; coupled transmission lines; microstrip lines; resonators; bandpass filter; coupled-line resonator; filter response; harmonic responses; microstrip parallel-coupled lines; step-impedance transmission-line compensation;

fLanguage

English

Journal_Title

Microwaves, Antennas & Propagation, IET

Publisher

iet

ISSN

1751-8725

Type

jour

DOI

10.1049/iet-map.2008.0070

Filename

4805196