小型內藏式天線經常遇到頻寬和輻射效能降低的問題。本文中我們設計與實做出使用傾斜饋入之內藏式寬頻平面單極天線，且具有全向輻射在寬頻的操作頻帶上。此天線在中心頻率為1.66GHz時有465MHz頻寬，最大交叉極化在1.8GHz時為-13dB，可用於GSM1800行動通信上。在修改的設計中我們在平面單極天線上做一斜向開槽，此設計在中心頻率為1.71GHz時有455MHz頻寬，包函了GSM1800、PCS1900通信頻帶，且在1.8GHz時最大交叉極化為-15dB。此天線的大小為40 mm*15 mm，在系統基板上只佔一小部分面積，適合內置於手持式行動裝置中。

An internal small antenna usually suffers from degradation in performance of impedance bandwidth and radiation patterns. In this thesis, we design and fabricate a broadband interior type planar monopole with an omni-directional radiation pattern over a wide operation band using a slant feeding strip. It has a measured impedance bandwidth about 465MHz with center frequency at 1.66GHz (1427 – 1892MHz) and the maximum cross polarization level about -13dB at 1800MHz, which is GSM1800 band in mobile communications. A modified design is an interior planar monopole with a slant slit. It has a measured impedance bandwidth about 455MHz with center frequency at 1.71GHz (1487 – 1942MHz), including GSM1800 and PCS1900 band, and the maximum cross polarization level about -15dB at 1800MHz. The antennas have the dimensions of 40mm*15mm which occupies a small size on the system board and they are suitable to be mounted within the mobile handset device.

Acknowledgements i
Abstract ii
Contents iii
List of figures and tables iv
Chapter 1 Introduction 1
1.1 An overview of monopole antennas 1
1.2 Characteristics of planar monopole antenna 2
1.3 Motives of this study 3
Chapter 2 Theory and characteristics of monopole antenna 4
2.1 Theory of monopole antenna 4
2.2 The characteristics of the feeding line 6
2.3 Antenna bandwidth and polarization characteristics 10
Chapter 3 Interior planar monopole with a slant feeding strip 12
3.1 Antenna design 12
3.2 Experimental results 14
3.3 Summary and discussion 27
Chapter 4 Interior planar monopole with a slant slit 28
4.1 Antenna design 28
4.2 Experimental results 30
4.3 Summary and discussion 43
Chapter 5 Conclusion 44
Reference 45

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