寬頻平衡式天線之設計

Abstract

在本論文中，我們設計了操作在ISM頻段(5GHz)無線區域網路的quasi-Yagi天線，並且使用各種不同的平衡不平衡器。為了達到較寬的頻寬，我們應用了series-fed天線結構。我們同時呈現了等效電路模型，並且推導設計公式，已得到更高的增益值。我們利用較容易取得的介質板材FR4，以實驗結果來驗證寬頻及增益的效果。

In this thesis, planar quasi-Yagi antennas fed by different kinds of baluns are designed for 5GHz WLAN systems including Marchand balun, via-hole fed balun, half-wavelength balun, and multisection coupled-line balun. To obtain wider bandwidth, series-fed antenna is investigated. We also present equivalent circuit model and derive design formula to obtain higher gain. They are implemented and measured at 5GHz with FR4 PCB and results show good enhancements in both bandwidth and gain.