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http://dx.doi.org/10.5515/JKIEES.2011.11.3.186

A Method for Improving Stopband Characteristics of a Dual-Band Filter  

Lee, Ja-Hyeon (Department of Electronics and Computer Engineering, Chonnam National University)
Lim, Yeong-Seog (Department of Electronics and Computer Engineering, Chonnam National University)
Publication Information
Journal of electromagnetic engineering and science / v.11, no.3, 2011 , pp. 186-191 More about this Journal
Abstract
This paper presents a simple and effective method for improving stopband rejection characteristics of previously studied dual-band filters. Small electric couplings were applied to the symmetrically positioned shunt resonators, which divided each transmission zero into two transmission zeros without any effect on passbands. We were able to achieve improved stopband rejection characteristics by these additional transmission zeros. For the filter application, we designed a dual-band filter with improved stopband characteristics using microstrip quasi-lumped elements. The electric couplings that control the location of transmission zeros are controlled by the distance between symmetric open stubs of the filter. The filter was fabricated with a relative dielectric constant of 3.5 and a thickness of 0.76 mm. The fabricated filter has a small size ($14.6{\times}13.2{\times}0.76$ mm) and a low insertion loss when compared with conventional filters.
Keywords
Dual-Band Filter; Electric-Coupling; Quasi-Lumped Elements; Transmission Zero;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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