利用四分之波長步階阻抗諧振器之共平面帶線式巴倫濾波器

Abstract

此論文中，提出以共平面帶線步階阻抗諧振器，構成單頻巴倫濾波器及平衡對平衡單頻及雙頻濾波器。其中，非平衡埠以寬邊微帶線接貫孔饋入，而平衡埠則以微帶線直接耦合饋入。由於共平面帶線對稱性佳，組成之諧振器擁有相當好的平衡性。另外，此論文中提出之濾波器的設計流程相當簡單，能以外部Q值曲線判斷所需耦合量對應之物理結構。所提出之濾波器均具有電路面積小、偽頻能推至四倍中心頻率外之優勢。實現所提出之電路使用板材為Duroid 6010，板厚25mil，介電係數10.2，且輸出入端皆使用微帶線。非常接近的模擬與量測結果証明了所提濾波器的可行性。

In this thesis, coplanar stripline (CPS) single-band balun filters and single- and/or dual-band differential filters using stepped-impedance resonator (SIR) are studied. The broadside microstrip in cooperation with via hole is applied to feed the unbalanced port whereas the microstrip direct coupling structure is applied to feed the balanced port. Due to the perfect balanced structure of a CPS resonator, all of the proposed filters show nearly perfect magnitude and phase balance. Applying the design curves to obtain physical parameter corresponding to appropriate external Q value, the filter can be easily designed. Moreover, the proposed filters are compact size and show a spurious frequency greater than four times the center frequency. All filters are fed by microstrip lines and are built on Duroid 6010 substrate with a substrate thickness of 25 mil and a dielectric constant of 10.2. The feasibility of the proposed filters is verified by well matched results of simulation and measurement.