In this paper, a miniaturized and harmonic suppression characteristics lumped-element branch-line coupler (BLC) with multi-layer ceramic capacitor (MLCC) elements and planar artificial transmission lines (ATLs) is proposed for ultra-high-frequency (UHF) applications. The new structure not only effectively reduces the occupied area to 4.8% of the conventional branch-line coupler at 0.925 GHz, but also has high harmonic suppression performance. The experimental results reveal that the proposed BLC features low insertion loss and compact size. At the center frequency of the UHF system, the occupied size of the proposed miniaturized BLC is merely 13.7(L) ×10.55(W) mm^2, or equivalently 0.06λ_g×0.05λ_g. The measured results indicate a bandwidth of more than 225MHz has been achieved while the phase difference between S_(21) and S_(31) is within 90°± 1°. Furthermore, the measured insertion loss is comparable to that of a conventional branch-line coupler. The new coupler can be easily implemented by using the standard printed-circuit-board etching processes with multi-layer ceramic capacitor (MLCC) elements and is very useful for wireless communication systems. The simulated and measured results are in good agreement, thereby verifying the design concept.
在本文中,提出了一種具有多層陶瓷電容器(MLCC)元件和平面人造傳輸線(ATL)的小型化和諧波抑制特性集總元件分支線耦合器(BLC),於超高頻帶(UHF)之操作應用。新的結構不僅有效地將佔用面積比傳統分支線耦合器減少到4.8%於0.925 GHz的操作設計,而且具有高諧波抑制性能。實驗結果表明,提出的分支線耦合器(BLC)設計具有插入損耗小,體積小的優點。在UHF系統的中心頻率下,所提出的微型分支線耦合器(BLC)的佔用尺寸僅為13.7(L)×10.55(W)mm^2,也相當於等效為0.06λ_g×0.05λ_g。測量結果表明,S_(21)和S_(31)之間的相位差在90°±1°之內,已達到超過225MHz的帶寬。此外,測量的插入損耗與常規分支線耦合器的插入損耗相當。通過使用具有多層陶瓷電容(MLCC)元件的標準印刷電路板蝕刻工藝,可以輕鬆實現新的耦合器,對於無線通信系統非常有用。模擬和測量結果非常一致,從而驗證了設計理念。