有限寬度背覆金屬共面波導饋入天線設計

Abstract

我們提出了使用有限寬度背覆金屬共面波導饋入的天線，特別的是我們用其有限寬度的共平面金屬接地面邊板當作天線。有限寬度背覆金屬共面波導饋入邊板天線的原型擁有不錯的天線增益以及小型的天線架構，可是此天線的交叉極化比較大。因此我們提出了兩種修正原本天線的方式去抑制交叉極化。我們也提出了另一種簡單的方式去增加原型的阻抗頻寬。最後我們提出了一個比原型在小一倍的小型化有限寬度背覆金屬共面波導饋入邊板天線。 我們也提出了有限寬度背覆金屬共面波導饋入圓形極化天線，利用了邊板的共振幫忙圓形極化的輻射，所得到的阻抗頻寬和軸比頻寬都比傳統的微帶線饋入近方形圓極化天線好。 我們最後提出了使用有限寬度背覆金屬共面波導饋入共平面微帶天線陣列，我們在設計此類天線時考慮了有限寬度邊板的效應，與使用無限大的金屬邊板、背板及介質有所不同，我們會在此本論文裡完整地探討此效應。 上述所有有限寬度背覆金屬共面波導饋入的天線，都有理論的探討及實驗的驗證。

The finite-width conductor-backed coplanar waveguide (CBCPW)-fed antennas are proposed. We use the side-ground plane as the antenna. The prototype of finite-width conductor-backed coplanar waveguide-fed side-plane ground has satisfactory antenna gains and compact size; however it has higher levels of cross-polarization radiation components. Therefore, we propose two modifications of the prototype to achieve the low levels of cross-polarization radiation components. The other modification of the prototype is to provide much wider impedance bandwidth than the original one. The more compact size of the antenna is proposed, too. All of the above can provide moderate impedance bandwidth, satisfactory gains, unidirectional radiation, and compact size of the antenna. The finite-width conductor-backed coplanar waveguide-fed circularly polarized antenna is also proposed. We utilize the side-plane resonances to assistant the circularly polarized radiation. The impedance bandwidth and axial ratio bandwidth are both better than the conventional microstrip-fed nearly square patch antenna. The finite-width conductor-backed coplanar waveguide-fed coplanar patch antenna array is proposed. We have considered the effect of finite ground with whole procedure of the antenna design. There are some differences between the CBCPW-fed antenna array with the infinite ground and substrate. We would give thorough discussion in this thesis. All of the above designs of finite-width CBCPW-fed antenna are theoretically studied and experimentally verified.