300 GHz波導管至平面式傳輸線轉接器

Abstract

本論文探討於300 GHz操作的波導管至平面式傳輸線轉接器，並先後提出兩種轉接結構。第一種是於波導管內設置金屬脊，調整脊高度使之漸變式遞減，將能量傳入以電路板中微帶線，微帶線上無須額外的匹配網絡。第二種是基於切比雪夫阻抗匹配法的轉接器，由波導管內的三階特徵阻抗轉換器組成，與四種電路板傳輸線(微帶線、基板合成波導、漸變式基板合成波導與背接金屬共平面波導)相接量測。 太赫茲電路較微波電路精密，需要非常重視尺寸與連接的問題。本論文在波導管的設計上，討論了法蘭設計，螺絲孔與定位銷設置等相關細節。坊間標準印刷電路板製程之傳輸線品質也在顯微鏡下仔細觀察分析。本論文採用了三種拋光方式，來改善電路板邊界粗糙之問題，並且藉由粗糙度量測及S參數量測，來比較拋光後的電路板狀態，並驗證轉接器之性能。

This thesis discusses waveguide-to-planar transmission line transitions operating at 300 GHz, and proposes two transition structures successively. The first transition structure is done by gradually decreasing the height of the ridge in the waveguide so that the energy can efficiently feed into the microstrip line in the printed circuit board. No additional matching network is required on the microstrip line. The second transition structure is based on the Chebyshev impedance matching method, which is composed of a third-order impedance converter in the waveguide. Four kinds of transmission lines (microstrip line, substrate-integrated waveguide, tapered substrate-integrated waveguide and grounded coplanar waveguide) are tested. Terahertz circuits require more fabrication precision than microwave circuits, so we need to pay more attention to the size and connection issues. In the design of the waveguide, this thesis discusses the design details of flange, screw hole, positioning pin, etc. The transmission line quality of the standard printed circuit board manufacturing process in the market is also carefully analyzed under a microscope. Three polishing methods are applied to improve the roughness of the circuit board boundary. The performances of the polished transmission lines are verified by the surface roughness measurement and S parameter measurement.