本論文中提出了具有倍頻諧波壓抑效果的微小化直交(90°)分合波器，和傳統的直交分合波器比較，文中所設計之直交分合波器具有較小面積及倍頻諧波壓抑的優點，本論文中提出針對三倍諧波壓抑和針對三倍及五倍諧波壓抑微小化直交分合波器，所使用方法為分別以T字型及十字架型的等效傳輸線來替代原本四分之一波長傳輸線，等效傳輸線在基頻時和傳統傳輸線響應相同，在特定諧波時會有帶拒濾波器的效果進而達到倍頻諧波壓抑，此外三倍諧波壓抑微小化直交分合波器在面積微小化的最佳化過程後較傳統直交分合波器減少約56%，而三倍及五倍諧波壓抑微小化直交分合波器在面積微小的最佳化過程後較傳統直交分合波器減少約24%的面積。 In this study, miniature quadrature hybrids with harmonic suppression are presented. In comparison to the conventional hybrids, the proposed ones achieve two features: compactness and harmonic suppression. Two hybrids, one with third harmonic suppression and the other with third and fifth harmonics suppression, are designed, fabricated, and measured. T-shaped or cross-shaped equivalent lines are used to replace the quarter-wavelength microstrip lines of the conventional hybrids. The equivalent lines achieve the same fundamental characteristic and act like bandstop filters at the particular harmonics to improve suppression. Moreover, after miniaturization, the proposed hybrid with third harmonic suppression achieves 56% size reduction as compared to the conventional hybrid as well as the proposed one with third and fifth harmonic suppression achieves 24% size reduction as compared to the conventional one. The miniaturization of the hybrid to decrease area of hybrids is also provided in the study.
