Microwave Circuit Design: A Practical Approach Using ADS

Chapter 5. Introduction to Microwave Active Devices

Chapter Outline

5.1 Introduction

5.2 Field Effect Transistor (FET)

5.3 Bipolar Junction Transistor (BJT)

5.4 DC Bias Circuits

5.5 Extraction of Equivalent Circuits

5.6 Summary

5.1 Introduction

Before 1970, available microwave semiconductor devices were largely diodes and Si BJTs (bipolar junction transistors). Gunn, IMPATT, varactor, PIN, and Schottky diodes were frequently used in microwave applications. A reverse-biased pn junction diode has a depletion capacitance that changes when the reverse-biased DC voltage changes. A varactor diode is a variable capacitor that utilizes this depletion capacitance property. The varactor diode is often used to adjust the oscillation frequency and it ...