應用於單頻段和多頻段之新型印刷式天線之設計及量測

Abstract

這篇論文中展示了三隻新型的印刷式天線。首先介紹一支2.4 GHz 的印刷式倒E型天線，它是一種改良的印刷式倒F天線，利用在開路支線端增加一個類似平行板電容的電容性負載來縮小天線的尺寸，而它的幅射場型相當於全向性，最大的天線增益有2.09 dBi 。接著介紹一支工作在2.4 GHz 和 5 GHz的雙頻天線，利用一個微帶線抗流器使電流在高頻時無法進入調整的金屬線中，而達到雙頻的效果，它在低頻的幅射場型相當於一般印刷式單極天線的場型，而在高頻則是接近全向性的場型，最大的天線增益在低頻有2.43 dBi 而在高頻有 4.58 dBi。最後再利用相似的原理設計一個工作在0.9 GHz、1.8 GHz、1.9 GHz和2.4 GHz的多頻天線，可做為GSM和WLAM應用整合的天線。

Three novel printed antennas for single- and multiple-band applications are exhibited in this thesis. First, we will show a printed inverted-E antenna which is modified from a printed inverted-F antenna but with a printed capacitance load to reduce the antenna size. It has an omni-directional radiation pattern with a maximum gain of 2.09 dBi. Then, we show a dual-band antenna with a microstrip choke for 2.4 GHz and 5 GHz applications. The microstrip choke prevents the current at higher band entering the tuning metal line. Its radiation patterns at lower band are like a printed monopole antenna and are omni-directional at higher band. The maximum gain is 2.43 dBi for lower band and 4.58 dBi for higher band. Finally, we utilize similar principle to design a multiple-band antenna at 0.9 GHz, 1.8 GHz, 1.9 GHz and 2.4 GHz. It is suitable for GSM and WLAN integration applications.