雙層漏波式微帶天線輸入阻抗之探討

The Investigation of Input Impedance for Double-Layer Leaky-Wave Microstrip Antennas

謝東宏(Tung-Hung Hsieh) ； 盧冠宇(Kuan-Yu Lu) ； 陳必偉(Pi-Wei Chen)

《臺北科技大學學報》 40卷1期 (2007/03) Pp. 49-58

https://doi.org/10.29768/JNTUT.200703.0005

摘要

在各類天線中，備受矚目的傳統式微帶天線受限於共振之運作方式而具有窄頻的特性，而漏波式微帶天線因邊傳邊漏之特性彌補了傳統式微帶天線窄頻之缺失。當再運用雙層結構時，此結構之特質與漏波式微帶天線結合更賦予了此天線更多的設計空間。然而雙層漏波式微帶天線基本參數中的Scattering參數之輸入阻抗部份卻尚未有完整之研究而限制雙層漏波式微帶天線之應用。為探討雙層漏波式微帶天線之輸入阻抗以了解此參數對天線之影響，因此本文乃引用傳統導波管輸入阻抗之計算概念來處理雙層漏波式微帶天線之輸入阻抗，天線空腔內電場分佈之確立可得空腔內電磁波之傳播功率而獲得分析所需之輸入阻抗參數。本文從probe輸入位置的改變得知，輸入位置作橫向與縱向移動皆可改變阻抗值；而雙層天線結構之厚度之不同也會影響阻抗值之大小，因而全方位的瞭解此參數對天線之影響。本論文所得之分析結果不僅提供了阻抗匹配之參考，也使得雙層漏波式微帶天線之基本參數更為完整而利於日後之應用。

關鍵字

雙層 ； 漏波式 ； 微帶天線 ； 輸入阻抗

並列摘要

Among all kinds of antennas, the traditional microstrip antennas have earned attention despite that its characteristic of narrow-band due to resonance. However, the leaky-wave type microstrip antennas can provide wide-band because of electromagnetic wave leakage while propagating, and this characteristic compensates the shortage of narrow-band behavior for traditional microstrip antennas. As combining the double-layer structure, and leaky-wave concept, the new antenna can provide more flexibility for design. However, the scattering parameter which plays an important role for input impedance is not investigated yet for double-layer leaky-wave microstrip antenna, and this shortage restricts their application. In order to investigate the input impedance and understand its influence on double-layer leaky-wave microstrip antenna, the purpose of this dissertation is to compute input impedance by using the cavity model concept. As electromagnetic wave is excited in a cavity, the propagation power in cavity is used to compute input impedance during analysis. The study of the research is based on changing of feeding location, such as vertical movement of probe, and various length or thickness of substrate which may affect the impedance. In addition, this research observes the relationship between input impedance and radiation pattern from all aspects to depict the effect of input impedance on antenna characteristics. The results of analysis do not only provide information for impedance matching, but also complete the basic parameters of double-layer leaky-wave microstrip antenna to ease design in the future. While applying to different structure of leaky-wave microstrip antennas, the simple and physical intuitive concept presented here is still eligible for the computation of their impedance upon the electric field in the cavity is obtained.

並列關鍵字

double-layer ； leaky-wave ； microstrip antenna ； input impedance