計畫名稱：具等埠阻抗之小型化Wilkinson不等功率分配器設計
執行起迄：2013/08/01~2014/07/31
總核定金額：564,000元
中文摘要：本計畫提出一個Wilkinson不等功率分配器，此功率分配器有別於傳統Wilkinson不等功率分配器，無須額外的阻抗轉換器就可以達到等埠阻抗效果，因此可以縮小電路尺寸。此功率分配器在設計上結合濾波器設計理念，適當設計各埠共振腔之間的耦合係數來達到不等功率分配的效果，並利用4埠180°耦合器設計概念，將隔離電阻放置在第四個共振腔上，透過180°耦合器設計理念來達到所需要的各埠阻抗匹配以及隔離度效果。所設計的Wilkinson不等功率分配器已製作在RO4003C微波基板上，並以網路分析儀加以量測。量測結果顯示此電路確實可以達到所需的3 dB功率分配特性，而且各埠在通帶具有至少10 dB的反射損耗，隔離度也有15 dB以上。此外，額外的傳輸零點和濾波器設計理念讓此電路具備很好的頻率選擇性。量測結果與電磁全波分析也具有很好的一致性。同時也設計了一個具有1:2不等功率的雙頻帶2.45/5.8 GHz功率分配器，除了三埠在設計兩頻帶內可以達到至少10 dB的反射損耗，量測的隔離度在兩頻帶內也有12 dB和 20 dB以上。雖然此一雙頻帶功率分配器在端埠必須加上阻抗轉換器，但此阻抗轉換器是來自於雙頻帶頻寬設計自由度的需求，如果僅需設計雙頻帶的頻寬比值，則可以移除阻抗轉換器就可達到端埠阻抗相同的架構。
英文摘要：A Wilkinson unequal power divider has been proposed. In contrast to a traditional Wilkinson unequal power divider, the proposed power divider has equal port impedance without additional impedance transformers. The size of circuit is hence reduced. The filter design concept is utilized to realize the power divider. With suitable coupling coefficients between each pair of port resonators, unequal power division can be achieved. For good isolation, the design concept of a 4-port 180° hybrid coupler is utilized. A resistor is attached in the fourth resonator for good impedance matching and isolation. A Wilkinson unequal power divider has been implemented with a RO4003C substrate and measured with a network analyzer. The measured results shows that the designed 3-dB power division ratio is achieved. The proposed power divider exhibits more than 10-dB return loss and at least 15-dB isolation in the passband. In addition, addition transmission zeros and the filter design technology make the circuit posses good frequency selectivity. The measured results also show good consistency with full-wave simulated data. A 3-dB unequal power divider with 2.45/5.8-GHz dual-band operation was also realized. In additional to 10-dB return loss at the dual frequency bands for each port, the measured 12/20 dB isolation at 2.45/5.8 GHz was achieved. The requirement of an impedance transformer at each port for this dual-band unequal power divider comes from the desired uncorrelated fractional bandwidth at each operation frequency. The impedance transformers could be removed if the ratio of fractional bandwidths is only designed.