雙頻串聯式饋入陣列偶極天線

Abstract

在本論文中，我們提出一個新型的雙頻陣列天線。CSRR共振腔本身可視為一個電容與電感並聯的結構。將它與微帶線結合以後利用並聯共振腔共振時開路的特性使電流在特定頻率下無法通過。利用此特性並透過適當的安排以後就能達到雙頻分工的效果。本論文以此作為天線的饋入網路，並透過平衡-非平衡轉換器將微帶線轉換為帶狀傳輸線後再對偶極天線進行激發，達到雙頻天線的效果。為了進一步擴展為陣列天線，我們引用了串聯式饋入的方法。串聯式饋入是利用傳輸線把天線做串接，因此能量會經由傳輸線傳送到各級天線中。此種饋入方式最大的好處是能減少饋入網路的面積，因此能降低能量在傳輸線傳送的耗損。透過串聯式饋入，我們將天線擴展為四乘一的雙頻陣列天線。此天線可以操作在5.96GHz和7.8GHz這兩個頻段。天線在這兩個頻段下的增益皆為5.96(dB)。而指向性分別為9.37(dB)和9.1(dB)。

In this thesis, we propose a novel-dual band array antenna. The Complementary Split-Ring Resonator (CSRR) behaves as a parallel LC resonator. We combine the CSRR structure with the suspended microstrip line and which leads to the current on the microstrip line will be cut off by the CSRR structure when it resonate. This electromagnetic property can be used to design a frequency diplexer and we use this frequency duplexer as the feeding network of the array antenna. Since the microstrip line cannot directly feed the dipole antenna, so we add the balun to convert the microstrip line to the parallel strip line. The basic dual band antenna had been successfully designed. In order to expand this dual band antenna to the dual band array antenna, we include the series feeding technique. This feeding technique not only reduces the area of the feeding network but also lower the loss of circuit. Therefore we can expand the dual band antenna to the 4 × 1 dual array antenna. This dual band array antenna can operate in 5.96GHz and 7.78GHz. The peak gains of these two frequencies are both 5.96 (dBi), and the directivity is 9.37(dB) and 9.1(dB) respectively.