微波主動元件之線性與非線性模型

Abstract

中文提要: 今日電腦輔助設計被廣泛地應用於類比，數位和微波電路中，電路模型使 用的範圍從簡 單線性到複雜非線性系統。在微波工程應用方面，商用 電腦輔助設計軟體一直持續在發 展，並且廣泛地被使用於微波積體電 路(MIC)和單晶微波積體電路(MMIC)的設計。通常 這些軟體所提供的 微波主動元件模型有限,不能滿足設計者在電腦模擬上的需要。而 且電腦輔助軟體資料庫，有時只有線性參數模型，缺少非線性模型無法模 擬複雜非線性 電路。對MMIC設計而言，如果沒有準確模型，根本無法 分析電路設計特性，同時製程與 元件工程師亦需倚賴模型，做為評估 元件製作是否正確，及製造良率之參考。由上面所 述可看出微波主動 元件之線性與非線性模型的重要性。 本文將介紹如何截取微波主動元件之線性與非線性模型參數，我們主要研 究兩種微波 電路中常用到的主動元件.一是射頻電晶體(RF BJT),另 一是砷化鎵場效電晶體 (GaAs MESFET)的線性與非線性模型 的建立。我們將以高頻量測為出發點，逐一將微 波主動元件之線 性與非線性模型參數截取出。 英文提要: Computer-aided design (CAD) of circuit systems is widely applied in areas such as analog, digital, and microwave circuit design. The device models including simple and linear to sophisticated large-signal nonlinear system could be applied to these CAD softwares. In microwave engineering, commercial CAD softwares have been developed and widely used by microwave engineers for the design microwave integrated circuit (MIC) and monolithic microwave integrated circuits (MMIC). Today, most active device models that go with microwave CAD softwares can't satisfy the demand of microwave engineers. Sometimes, they have only the linear circuit models but lack of the nonlinear circuit models. As a result, we can't simulate complex microwave circuits. Therefore, the linear and nonlinear circuit models of active devices can be used to characterize the device technological process and are very important in microwave circuits design and performance's analysis of the device such as gain, noise etc.. In this thesis, we will describe how to extract linear and nonlinear circuit models of microwave active devices. We will focus on two types of microwave active devices which are frequently used by microwave engineers: one is the RF BJT, and the other is GaAs MESFET.