多頻帶阻絕天線之設計與電路模型分析

本論文提出了多頻帶的多輸入多輸出天線系統，相較於大部分的多頻天線用結構上的延伸來增加額外的頻帶，本論文以頻帶阻絕的方式來達到多頻的效果。本論文中先分析V形槽孔濾波器在傳輸線時的特性，再與超寬頻天線整合，將過V形槽孔做適當的調整後，過濾掉不需要的頻帶，即可設計出一個多頻帶的天線。此流程的優點在於天線本身不需要重新設計，只要將V形槽孔的參數重新調整後，就可以將天線做不同的應用。　　除了與天線整合，我們也將同樣的概念用於提高天線之間的隔離度。兩支天線在近距離擺放時，由於共用接地面，容易產生電磁耦合的效應，造成天線匹配與效率變差，在天線共用的接地面加上槽孔，可以利用其頻帶阻絕的特性抑制電流，提升兩支天線間的隔離度。　　本論文中提出了槽孔型濾波器、單極超寬頻天線以及帶阻天線之等效電路模型，由電路模型可以更加理解其工作原理，天線的部分也透過實作與模擬結果互相驗證，量測與模擬結果相當吻合。

關鍵字

頻帶阻絕；多頻天線；單極天線；多輸入多輸出；超寬頻

並列摘要

In this thesis, a multi-band MIMO antenna system is proposed. Compared to the traditional multi-band antennas using extended geometry to obtain additional operation bands, we employed the band-notching concept to achieve multi-band operation. We started with the analysis of the microstrip line over a V-shaped defected ground structure. Then, we applied V-slots on the UWB monopole antenna. By properly designing the slot dimension, we can notch out unwanted bands to complete a multi-band antenna. Using the proposed design method, the antenna can be easily modified for various applications simply by re-designing the V-slots without changing the antenna dimension. The mutual coupling is a critical issue when two antennas are closely spaced. We also applied the band-notched slots on the common ground. The isolation of two antennas was successfully enhanced. The equivalent circuit models of V-shaped DGS, UWB monopole and tri-band notched antenna are proposed. Through the circuit model, we have a deeper insight of the working principle of our designs. The prototype of UWB monopole antenna, tri-band notched antenna and multi-band MIMO antenna system were designed, built, and tested with a very good agreement between the simulated and measured results.

並列關鍵字

band-notch ； defected ground structure (DGS) ； MIMO ； monopole ； multi-band antennas ； UWB

參考文獻

[1] Y. D. Dong, W. Hong, Z. Q. Kuai, and J. X. Chen, “Analysis of planar ultrawideband antennas with on-ground slot band-notched structures,” IEEE Trans. Antennas Propag., vol. 57, no. 7, pp. 1886–1893, Jul. 2009

[2] Q.-X. Chu and Y.- Y. Yang, “A Compact Ultrawideband Antenna With 3.4/5.5 GHz Dual Band-Notched Characteristics”, IEEE Trans. Antennas Propag., vol. 56, no. 12, pp. 3637–3644, Dec. 2008.

[3] K. S. Ryu and A. A. Kishk, “UWB antenna with single or dual band-notches for lower WLAN band and upper WLAN band”, IEEE Trans. Antennas Propag., vol. 57, no. 12, pp. 3942 -3950, Dec. 2009.

[4] A. Habashi, J. Nourinia, and C. Ghobadi, “Mutual coupling reduction between very closely spaced patch antennas using low-profile folded split-ring resonators (FSRRs),” IEEE Antennas Wireless Propag. Lett., vol. 10, pp. 862–865, 2011.

[5] K.-J. Kim, W.-G. Lim and J.-W. Yu, “High Isolation Internal Dual-Band Planar Inverted-F Antenna Diversity System with Band-Notched Slots for MIMO Terminals,” Proc. of 36th European Microwave Conf., pp. 1414-1417, Sep. 2006

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多頻帶阻絕天線之設計與電路模型分析

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