Electromagnetic Fields and Waves, 3rd Edition by Pearson

CHAPTER 9

TRANSMISSION LINES-II (IMPEDANCE MATCHING IN HIGH FREQUENCY LINES)

9.1 INTRODUCTION

Transmission lines operating at Ultra High Frequencies (UHF) ranging from 300-3000 MHz or wavelengths from 100 cm to 10 cm have conductor and dielectric losses which can be neglected when the physical length of the transmission line is small. In this case, the total attenuation is nearly zero and the loss is primarily due to the phase shift. Hence, a UHF line is considered to be lossless if and only if the line length is assumed to be small. The UHF lines can become resonant at particular frequencies when the line is terminated with extreme impedances like the open or short circuit.

When a voltage is applied to a transmission line, it produces an incident ...