Section 6 1 TRƯỜNG ĐIỆN TỪ

6 1 Transmission Line Slide Presentations for ECE 329, Introduction to Electromagnetic Fields, to supplement “Elements of Engineering Electromagnetics, Sixth Edition” by Nannapaneni Narayana Rao Edwar[.]

Introduction to Electromagnetic Fields,

to supplement “Elements of Engineering

Electromagnetics, Sixth Edition”

by

Nannapaneni Narayana Rao Edward C Jordan Professor of Electrical and Computer Engineering

University of Illinois at Urbana-Champaign, Urbana, Illinois, USA

Distinguished Amrita Professor of Engineering Amrita Vishwa Vidyapeetham, Coimbatore, Tamil Nadu, India

Transmission Line

Parallel-Plate Line

Neglect fringing (d << w).

x

y z

Consider the circuit

TransmissionLine

Equations

L = w d , inductance per unit length

G = d w, conductance per unit length

C = d w , capacitance per unit length

x

y z

Distributed Equivalent Circuit

Assumes perfect conductors but lossy dielectric

Transmission-Line Equations

L = Inductance per unit length (H/m)

C = Capacitance per unit length (F/m)

G = Conductance per unit length (S/m)

In general, conductors are also lossy Then, the wavesare not exactly TEM waves

R = Resistance per unit length (/m)

(Perfect Conductors, Perfect Dielectric)

WaveEquationCombining, we obtain

d << w

L   d w

C   w d

Ground Plane

w d

Shielded Strip Line