微帶線帶通濾波器之諧波抑制及其微小化

Abstract

本論文提出以鋸齒型耦合微帶線結構，抑制耦合微帶線帶通濾波器所產生的二次諧波，使用鋸齒型結構是為了使兩個實際的激發模相位速度相等，使設計出來的濾波器能有較寬的截止頻帶及令人滿意的衰減程度。此外，在通帶兩旁頻率響應對稱性也因此改善，模擬和實際量測的結果相當一致。本論文亦將鋸齒結構應用到髮夾型共振腔濾波器的設計，除了有抑制二次諧波的效果外，亦達到電路微小化的效果。

Corrugated coupled microstrip lines are proposed to design planar microwave filters with suppression of spurious response at twice the center frequency（2f0）. The corrugated structure is designed to equalize the phase velocities of the two eigen-modes of the coupled lines. The designed bandpass filters have a wide upper stopband with satisfactory attenuation levels. In addition, the symmetry of the passband response is improved. The corrugated structure is also applied to design hairpin resonator filters for circuit miniaturization. Measured results of six fabricated circuits show that the idea works very well.