Ku頻段修正型功率分配器及適用於Wi-Fi和WiMAX寬頻共平面波導平衡至非平衡轉換

Abstract

數位傳播的衛星電視訊號操作於Ku頻(12GHZ~14GHZ)，在車用衛星電視系統中，需要一個24路的功率分配器將訊號傳送至由24個偶極天線組成的陣列天線。然而，功率分配器在Ku頻段有互耦及接合點效應的問題。本文嘗試改變Wilkinson功率分配器，將λ/2傳輸線加入λ/4傳輸線中及隔離電阻和輸出端，以改善上述的問題。 現今有相當多的無線技術，為了涵蓋更多的無線規格需要寬頻的元件。文中以共平面波導的方式實做一個適用Wi-Fi和WiMAX頻段寬頻的Marchand平衡至非平衡轉換。頻寬取決於阻抗的比值，共平面波導結構可以輕易的實現高阻抗和低阻抗，達到寬頻的效果。

Digital broadcast satellite transmits signal in the Ku frequency range (12 GHz to 14 GHz ). To feed the array antenna composed of 24 dipoles, we need a 24-way power divider. However, power divider in Ku band suffers junction effects and mutual coupling. We modified the equal-split Wilkinson power divider by adding λ/2 transmission lines to λ/4 branches and isolation resistor to output ports to overcome those problems. There are a lot of wireless technologies in the world. To include more wireless standards, broadband devices are required. The broadband balun has the potential to provide various wide-band applications that are included Wi-Fi and WiMAX. We will develop a broadband Marchand balun using Co-planar waveguide (CPW) structure. Bandwidth depends on impedance ratio, and it is easy to realize high and low impedance in CPW by spacing the gaps and shunting more transmission lines.