
Circuit Theorems
211
The role of the antenna is to match circuit/air impedances. Without the
antenna the signal cannot propagate out of the circuit and is reected back,
and the antenna impedance matches the transmitter output impedance
(Figure6.31).
6.9.3 Maximum Voltage or Current Transfer
Here we will consider the conditions we must satisfy to transfer the maximum volt-
age value from the source to the load, realizing what is referred to as impedance
bridging, since it is a bridging connection if the Z
L
device does not appreciably
load the Z
S
component, so that no power is transferred.
An example of impedance bridging comes from the audio ampli ...