高頻傳輸線的製作及利用電光取樣法量測其介電特性

Abstract

我們製作了以氮化鎵及藍寶石(sapphire)為基底的共面式波導傳輸線，並以電光取樣技術，量測元件上的高頻駐波特性。在本論文中，我們利用了光導開關具有將光訊號與電訊號做諧波混頻的特性，並結合雷射時序紊亂度的抑制系統，使光源與微波訊號同步，以達成量測的結果。利用本技術在相位量測上的優越靈敏度，我們分析了於不同頻率時微波信號的駐波振幅與相位。這個技術使得我們可以量測微波傳輸線的元件特性，並因此而獲得在不同頻率下樣品的有效介電常數或折射係數等重要參數。

Coplanar waveguide transmission lines are fabricated for traveling wave measurement by electro-op tic sampling system (EOS) which use short pulse Ti:Sapphire Laser as the light source. EOS technique allows accurate and convenient determination of key parameters of microwave transmission lines, such as effective dielectric constant at different frequencies and dispersion characteristics. Taking advantage of the sensitivity for phase detection of EOS technique, we measured the phase data of the micro-wave traveling wave in transmission line devices up to 2GHz. Effective dielectric constant for transmission lines on GaN wafers is 5.90 at frequency 1GHz , and is 4.88 at 1GHz and 5.33 at 2GHz for transmission lines on sapphire substrates.