毫米波低成本菲涅爾極板透鏡天線設計

Abstract

在本論文中，設計、製造和量測了低成本的菲涅爾極板透鏡天線。該天線由產生球面波前的喇叭天線以及將球面波前轉換成平面波遠場的菲涅爾極板透鏡所組成。具體來說，這一類的菲涅爾極板結構是在常用於為波頻段的低成本介電質基板FR4實現的。與導波結構在基板內傳波不同，此種結構的波是散射，包括了在基板上的穿透與反射。因此在有損介電質中吸收的能量相對不那麼顯著。此外，獨立介電質板是類法布立－培若結構，因此必須適當的選擇介電質基板的厚度，來獲得操作頻帶下最大的透射率。另外，偏移的菲涅爾極板透鏡也被用於讓主波束向偏移角輻射。本文作者實施了幾個變形的菲涅爾極板透鏡，用於觀察其偏移的主波束角度，量測與模擬的結果大致符合。

In this thesis, a low cost Fresnel Zone Plate lens antenna was designed, fabricated and measured. The antenna under consideration consists of a horn antenna for generating the spherical wave front, and a Fresnel Zone Plate lens for converting the spherical wave front into the plane wave in far field. Specifically, such a class of Fresnel Zone structures was implemented on a low-cost dielectric substrate, FR4, which is commonly used in microwave region. Different from the guided-wave structure, the wave is scattering, which includes the transmission and reflection, by the thin dielectric slab rather than propagating within it; thus, the energy absorbed by the lossy dielectric is relatively less significant. Additionally, the free-standing dielectric slab is a Fabry-Perot-like structure, the dielectric thickness has to be properly chosen to obtain maximum transmission in the operation frequency bandwidth. Furthermore, the offset Fresnel Zone Plate lens was also developed to have the main-beam radiate toward an offset angle. This author has implemented several deformed Fresnel Zone plate lenses for observing the offset radiation main-beam angles; the agreement between the measured and simulated results, in general, is good.