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|Other Titles: ||Investigation of ground size reduction and array application for the planar Notch antenna|
|Authors: ||翁律淨;Wong, Liu-jing|
|Keywords: ||凹槽天線;彎折傳輸線殘段;藍芽;天線陣列;notch antenna;bent open transmission line stub;Bluetooth;WiMAX;array antenna|
|Issue Date: ||2010-01-11 07:12:21 (UTC+8)|
本論文藉由電容性金屬殘段(stub)負載技術設計一小型全平面式反J形凹槽天線，其可能應用為一操作在2.45 GHz ISM頻帶且可支援行動電話及其配備(如藍芽耳機)所需的小型天線，用以取代低溫共燒陶瓷(LTCC)晶片藍芽天線；本論文並進一步利用此凹槽天線為元件，設計一高增益的線形陣列天線。
有關本天線元件的設計，首先探討在一0.8公釐厚的FR4板上(接地面尺寸為30×40mm2)的四分之一波長的一字形凹槽天線，再將凹槽予以彎曲成反J形，並引進一個L形金屬殘段(stub)來提供電容性負載以進一步縮小化凹槽，最後配合凹槽結構將微帶饋線適當彎曲以使整個天線結構(凹槽加上殘段及三折微帶線)的尺寸縮小到7.94×7.41 mm2的占用面積(occupation area)。惟接地面尺寸維持為30×40mm2，因此，本論文並探討了凹槽結構參數對天線特性的影響，並藉此以進一步將接地面的尺寸縮小為30×14mm2，此時的10dB頻寬仍有50MHz。
實測結果顯示此凹槽天線的H-plane輻射場型具有全向性，其增益為3.29dB左右。另外，本論文亦探討了該凹槽天線與手機電路板整合後的效應，為此，我們將一接地面的尺寸縮小成只有14×14m m2的反J形凹槽天線搭載在一真實尺寸的手機電路板(100×60m m2)上，以模擬與真實手機結合的情況，此時的10dB頻寬仍有50MHz。
This thesis reports a miniature monopole notch antenna implemented by suitably meandering the notch into inverted J shape and being seriously coupled to anopen transmission line stub. The possible application of the proposed antenna is for the handset and its accessories such as the Bluetooth earphone as a substitution for the LTCC Bluetooth chip antenna. In addition, the proposed notch antenna structure is employed as the antenna element to design a linear antenna array of high gain.
In this thesis, a simple notch is suitably meandered to into inverted J shape and a bent and asymmetrical open transmission line is introduced to capacitively couple the notch antenna on a ground plane in order to achieve the reduction of antenna size. The purpose is to utilize a cheap PCB process and/or PCB board to implement a planar antenna without the use of 3D structure and the mechanical process, also to avoid the use of the LTCC (Low-temperature co-fired ceramic) process.
As the routine of the design process, a simple quarter-wavelength notch residing on a FR4 board with thickness 0.8mm (with the ground size 30×40mm2) is considered first. The notch is then suitably meandered to into inverted J shape and a bent L-shapedopen transmission line stub is introduced across the notch as a capacitive load to the notch antenna to reduce the antenna size. The microstrip fed is also suitably bent to match upwith the inverted J shape notch such that the total occupation area of the whole antenna structure is reduced to 7.94×7.41 m m2 which includes the notch, the open stub and the microstrip feeding part. It should be mentioned that the ground size 30×40mm2 is still maintained. The influences of antenna structure parameters upon the antenna input impedance are also studied, by which the antenna design with the ground size reduced to 30×14mm2 can be easily carried out.
The experimental results show that the H-plane antenna pattern is omni-directional for the proposed notch antenna of inverted J shape, while the antenna gain is 3.29dB. The thesis also studies the effect of the integration of the notch antenna with a large ground plane to simulate the practical situation in usage. Thus, theproposed antenna of inverted J shape notch with small ground size of 14×14m m2is connected with a large ground plane of size 100×60m m2, of which the 10dB bandwidth is ~50MHz.
Finally, the size of proposed notch antenna of inverted J shapeis scaled down for higher frequencies. The purpose is to have the new notch antenna operate in the 3.5GHz(3.4~3.6GHz) WiMAX band, and to utilize it as the antenna element to design a linear antenna array of high gain for WiMAX application. Different orientations for the antenna element are studied, while, on the other hand, the antenna array made of simpleelement with quarter-wavelength notch is also tested.
|Appears in Collections:||[電機工程學系暨研究所] 學位論文|
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