A miniaturized parallel-coupled microstrip filter using over-coupled end stages with symmetrical tapped-line structure

作者：Lin Kun Ying; Liao Shry Sann^*

来源：Microwave and Optical Technology Letters, 2008, 50(9): 2271-2274.

DOI：10.1002/mop.23675

• parallel-coupled filter
• harmonic suppression
• stepped-impedance structure
• tapped-line

In this article, a miniaturized parallel-coupled microstrip filter is presented. The miniaturized design saves 80% circuit dimension compared to the conventional parallel-coupled over-coupled end stages filter with the symmetrical tapped-line structure. Several design methods and miniaturization techniques were involved in this study to achieve 5f(0) stopband suppression, including symmetrical tapped-line, stepped-impedance structure, bended and folded of transmission lines, and the coupling effect of microstrip-lines. Also the asymmetrical tapped-line structure is fabricated to achieve 6f(0) stopband suppression. Good agreements between the simulated and measured results were also observed in all above cases. Furthermore, no lumped elements, via-holes, and bonding wires are necessary for this miniaturized coupler, making it very useful for the modern wireless communication systems.

• 出版日期2008-9