具高指向性及窄波束之倒 F 超穎天線陣列設計

The Design of High-Directivity and Narrow Beam-Width Inverted-F Metamaterial Antenna Array

本文利用電磁能隙（Electromagnetic Band-Gap，EBG）反射器激發電磁場的原理，設計出具有超穎材料特性的電磁能隙-倒F陣列（EBG-InvF Array）。操作頻率6 GHz對應的電磁波波長為50 mm，使用數值方法計算天線架構中實際維度，形成具電磁能隙之倒F天線陣列。接著在金屬貼片上使用鑽孔技術，連接金屬與接地面，並結合電磁能隙反射器，進而形成具超穎材料特性之電磁能隙倒F天線陣列。此具超穎材料特性之電磁能隙倒F天線陣列的響應與天線陣列大小，排列方式，饋電支柱半徑及饋入位置有關。為進一步驗證超穎材料特性，幾種電磁能隙-倒F天線陣列與相關參數設計被探討與模擬。文中提出具4支倒F直立陣列排列天線、6  6個正方形陣列的貼片所形成的反射器，饋電支柱半徑1.2 mm，模擬結果發現在低頻4 GHz所產生的模態為超穎材料所激發產生。此具超穎材料特性的天線陣列之反射係數為-19.49 dB，最大增益為13.45 dB，半功率波束寬度為38°，具有高增益、高指向性的天線特性。此天線可操作在S波段(2 GHz到4 GHz)與C波段(4 GHz到8 GHz)範圍。

 

The Electromagnetic Band-Gap inverted-F antenna array with metamaterial properties is designed for the applications of S-band and C-band. The numerical method is applied to estimate the dimensions of the designed. The patch matrix as the electromagnetic band-gap reflector is characteristics of metamaterial properties and can provide an extra radiation mode through substrate vias technology. The performances of the designed antenna are related to the feeding position, the size of the vias and the arrangement of the antenna array. The four inverted-F antennas placed in a line arrangement and the 6  6 patch matrix with vias are constructed and simulated. The radius of circular vias is 1.2 mm. It is observed that the extra radiation mode at 4 GHz is excited when operated at 6 GHz. The performances of the designed antenna array at 4 GHz are investigated. The reflection coefficients of -19.4 dB, realized gain of 13.45 dB and half-power beam-width of 38° are obtained.