Microwave Circuit Design: A Practical Approach Using ADS

Chapter 3. Transmission Lines

Chapter Outline

3.1 Introduction

3.2 Parameters

3.3 Coaxial and Microstrip Lines

3.4 Sinusoidal Responses

3.5 Applications

3.6 Discontinuities

3.7 Summary

3.1 Introduction

Figure 3.1 shows an example of a high-frequency circuit fabricated on a 100-μm-thick GaAs substrate. In the circuit (a three-stage 28 GHz GaAs pHEMT LNA), the voltages and currents in the line shown in the figure generally are functions of position at a high frequency. The pair of voltages (V₁ and V₂) and currents (I₁ and I₂) are simply considered to be equal at a low frequency, as the line acts as a simple connection. However, the pair of voltages and currents at these two points becomes unequal as the frequency increases. The shape of the ...