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標題: | 77GHz 車用防撞雷達系統之頻率波束掃描天線 Frequency beam-steering antennas for 77GHz car radar system |
作者: | Shan-Fong Hong 洪山峰 |
指導教授: | 盧信嘉 |
關鍵字: | 波導開槽天線,波束掃描天線,汽車防撞雷達, waveguide slotted antenna,beam steering antenna,car collision avoidance radar, |
出版年 : | 2011 |
學位: | 碩士 |
摘要: | 本論文實現77GHz頻率波束掃描天線,透過頻率的改變,即可改變波束的方向。主要實現於兩種被動製程,分別為達泰 (Darfon and Thales Microcircuits Corp.)公司提供的低溫共燒陶瓷(low temperature co-fired ceramics, LTCC) 製程。另一個為Rogers RO4003C板材。
天線設計上,採用介質基板波導實現漏波波導開槽天線架構,利用陣列方式來提升天線的增益。並達成波束隨頻率掃描的效果。採取單一饋入,以簡化饋入設計。此種架構不需要使用相位合成器,能夠更加降低雷達系統的整體價格。然而此種架構有頻寬小的問題,因此,在饋入架構方面要特別設計,此論文採用接地共平面波導至基板介質波導達成模態轉換與阻抗匹配。並且,在陣列天線邊界,加入鋸齒狀邊界,抑制爬行波,進而達到乾淨的極化。二維 4×7 天線陣列被實現於 LTCC 製程上,在76GHz到78GHz 頻帶內,天線指向性18dBi,天線增益15dB,使用頻帶內,|S11|<-10dB,極化隔離程度30dB以上,尺寸為20mm×10mm。一維1×8陣列天線和二維4×8天線被實現於RO4003C製程上。一維天線陣列,在76GHz到78GHz頻帶內,天線指向性13dBi,天線增益11dB,使用頻帶內,|S11|<-10dB,極化隔離程度30dB以上,尺寸為8.23mm×33mm。二維天線陣列,在76GHz到78GHz頻帶內,天線指向性17dBi,天線增益15dB,使用頻帶內,|S11|<-10dB,極化隔離程度30dB以上,尺寸為45mm×16mm。 This thesis presents the implementation of frequency beam-steering antennas for 77GHz car radar system. Two processes we used are low temperature co-fired ceramics (LTCC) provided by Darfon and Thales Microcircuits Corp., and Roger RO4003C. We use waveguide slotted array antenna on substrate integrated waveguide (SIW) to realize these antennas. This structure needs only one input to achieve frequency scan. It can replace traditional frequency scanning system which is implemented by using more than one antennas and phase shifters. By using this architecture, we can lower the cost of the total radar system. However, the structure has narrow bandwidth, so the input structure should be designed carefully. The grounded coplanar waveguide (GCPW) to SIW transformer is adopted to achieve mode and impedance transformation. Moreover, zigzag boundary is utilized on the edge of the antenna array to minimize creeping wave, and to get pure polarization. The performances of a two-dimension 4×7 antenna array implemented on LTCC are: from 76GHz to 78GHz, antenna directivity is about 18dBi, antenna gain is about 15dBi. The return loss is better than 10dB, cross polarization isolation is better than 30dBi with size of 20mm×10mm. The performances of a linear 1×8 antenna array implemented on RO4003C are: Directivity is 13dBi, gain is about 10dBi. The return loss is better than 11dB, cross polarization isolation is better than 30dB with size of 8.23mm×33mm. The performances of a two-dimension 4×8 antenna array implemented on RO4003C are: from 76GHz to 78GHz, directivity is about 17dBi, gain is about 15dB. The return loss is better than 15dB, cross polarization isolation is better than 30dB with size of 45mm×16mm. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/9657 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 電信工程學研究所 |
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