ENGINEERING TRIPOS PART IB - 2012/2013
PAPER 5 - ELECTRICAL ENGINEERING (3)
Electromagnetic Fields and Waves
Leader: Prof. A. Ferrari
Timing: Weeks 6-8 Lent term
Structure: 6 lectures, 2 lectures/week
- Starting from the first
year background work of phasors, capacitance and inductance, the aim is to
explain why one needs both E and H to describe electromagnetic waves and
to show how these waves propagate in free space.
As the frequency of electronic circuits rises, one can no longer assume that
voltages and currents are instantly transmitted by a wire. The objectives of
this course are that students should be able to:
- Appreciate when a wave
theory is needed.
- Derive and solve simple
transmission line problems
- Understand the importance
of matching to the characteristic impedance of a transmission cable.
- Understand basic principles of EM waves propagation in free-space, across interfaces and use of antennae. .
- Descriptive introduction of
how information is sent along wires and through free space.
- A descriptive introduction
of propagation along two wires. Capacitance per unit length. Inductance
per unit length. Resistance per unit length.
- Equations for V and I in differential form. Normalisation to a characteristic impedance.
- Solutions - forward and
reverse waves - phase velocity and significance of characteristic
impedance. Effects of load resistances of the wrong characteristic
- One dimensional wave motion
with Maxwell's equations seen as a transmission line analogy with E
corresponding to V and H corresponding to I. Implications for transmission
in free space and along optical fibres (descriptive only).