CHAPTER 2 - Conveying Power at Radio Frequency
60
This current flows through the capacitor in the opposite direction to the current which initially
charged it to E/2 volts as the incident pulse travelled to the end of the line (Figure 2.5-33).
Figure 2.5-33 Direction of flow of incident and reflected currents through shunt capacitors in a short-circuited line
From the point of view of the line however, the reflected "loop" current travels in exactly the same
direction as the incident one hence, unlike the open-circuit case, the reflected current has the same
amplitude and same polarity as the incident one (Figure 2.5-33). The reflected voltage on the other
hand maintains the same amplitude but has opposite polarity to the incident one. This is the
opposite of what happens in the open circuited case and is shown in Figure 2.5-34.
Figure 2.5-34 Pulse travelling back towards generator. Reflected current and voltage.
Subsequently current loops are yet again created which allow the pulse to travel back towards the
generator (Figure 2.5-35 and Figure 2.5-36) until the pulse is eventually absorbed by the generator
(Figure 2.5-37).
INCIDENT
CURRENT
REFLECTED
CURRENT
I
E
-E/2
+
-E/2
Conquer Radio Frequency
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