利用背腔式槽孔線結構之多頻段天線設計

Multi-band Antenna Design using Cavity-backed Slots

邱志豪(Chih-Hao Chiu)

指導教授 ： 丘增杰

國立中央大學/資訊電機學院/電機工程學系/碩士(2011年)

摘要

本論文主要提出一種新型線性極化之背腔式槽孔天線。其架構包含輻射槽孔與空腔，並採用於微帶線耦合饋入之方式。由於此架構有不同邊之輻射與耦合開口，天線會產生雙向輻射，為了使F/B比(Front to Back Ratio)更好，本文利用調整參數之方式改善F/B比。而此天線設計可以利用不同之饋入方式產生多頻或寬頻效果，並由同一槽孔輻射出去，且可將金屬外表之特性與高速移動裝置或金屬外殼做結合。在本文中使用新型背腔式槽孔天線設計出三頻與寬頻之應用。三頻天線設計主要先設計在低頻GPS(1.575GHz)以決定共振腔與輻射開口之大小，之後再使用開路殘段之匹配電路方式，設計出WLAN(2.45GHz)之頻段。最後再利用二分之波長共振器將能量從微帶線耦合，並藉由槽孔耦合饋入之方式，設計出DARS(2.34GHz)之頻段。而在GPS (1.575GHz)、DARS (2.34GHz)與WLAN (2.45GHz)的頻段中之最大增益分別為2.82 dBi、4.67 dBi與5.54dBi。寬頻天線則是在饋入末端使用一個50歐姆之負載阻抗以增加其頻寬，並設計在S-Band頻段內之3~4GHz應用，其頻寬為33%，最大增益範圍從1.89 ~ 3.76dBi。而上述之寬頻與三頻天線都已透過模擬與量測之方式，實際驗證出具有良好之特性。

關鍵字

空腔 ； 背腔式槽孔天線 ； 槽孔天線

並列摘要

A novel design of linearly-polarized cavity-backed slot antennas is presented in the thesis. The antenna, which consists of a radiating slot and cavity, is fed by a microstrip through coupling apertures. Owing to two slots located at different horizontal positions, the front to back ratio of the antenna can be improved. This technique takes advantage of different microstrip-fed coupling methods to generate multiband or wideband cavity-backed slot antenna with only one slot. Furthermore, this antenna can be mounted or integrated within the high-speed moving platform or metal outer cases. In the thesis, Designs of tri-band and wideband cavity-backed slot antennas are studied. The tri-band antenna is designed for GPS(1.575GHz)、DARS(2.34GHz) and WLAN(2.45GHz) applications. The low frequency is first designed to decide the size of cavity and slot. Then the second high frequency is designed by using open-stub matching network. Finally, the energy from the microstrip feed is coupled into the half-wavelength resonator through an electrically aperture to excite the radiation for first high frequency. The peak gain of tri-band antenna is 2.82 dBi at 1575 MHz, 4.67 dBi at 2340 MHz, and 5.5 dBi at 2450 MHz.. For the wideband antenna, it is a two-port device. One is the feed of the antenna while the other is connected to a 50ohm load. This technique can enhance bandwidth in S-Band applications. The bandwidth of wideband antenna is 33%. The peak gain of wideband antenna is from 1.89 dBi to 3.76 dBi. The wideband and tri-band cavity-backed slot antennas mentioned above have been verified and have good performances.

並列關鍵字

cavity-backed slot antenna

參考文獻

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