PASCO WA-9316A Complete Microwave Optics System - Manual (Page 18)

Experiment Guide Experiment 5: Polarization
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4. Set up the equipment as shown in Figure 5.4. Reset the
Receivers angle to 0-degrees (the horns should be ori-
ented as shown with the longer side horizontal).
5. Record the meter reading when the Polarizer is aligned at
0, 22.5, 45, 67.5 and 90-degrees with respect to the hori-
zontal.
6. Remove the Polarizer slits. Rotate the Receiver so the
axis of its horn is at right angles to that of the Transmit-
ter. Record the meter reading. Then replace the Polarizer
slits and record the meter readings with the Polarizer slits
horizontal, vertical, and at 45-degrees.
Questions
1. If the Receiver meter reading (M) were directly proportional to the electric field component (E) along its axis, the meter
would read the relationship M = M
o
cos  (where  is the angle between the detector and Transmitter diodes and M
o
is the
meter reading when = 0). (See Figure 5.2). Graph your data from step 2 of the experiment. On the same graph, plot the
relationship M
o
cos . Compare the two graphs.
2. The intensity of a linearly polarized electromagnetic wave is directly proportional to the square of the electric field 
(e.g., I = kE 2 ). If the Receiver’s meter reading was directly proportional to the incident microwave’s intensity, the meter
would read the relationship M = M
o
cos 2 . Plot this relationship on your graph from question 1. Based on your graphs, dis-
cuss the relationship between the meter reading of the Receiver and the polarization and magnitude of the incident micro-
wave.
3. Based on your data from step 5, how does the Polarizer affect the incident microwave?
4. Can you explain the results of step 6 of the experiment. How can the insertion of an additional polarizer increase the signal
level at the detector? (HINT: Construct a diagram like that shown in Figure 5.2 showing (1) the wave from the Transmit-
ter; (2) the wave after it passes through the Polarizer; and (3) the component detected at the detector diode.)
Angle of
Polarizer Meter
Reading
0° (horizontal)
22.5°
45°
67.5°
90° (vertical)
Figure 5.4: Equipment Setup
Angle of
Slits Meter
Reading
Horizontal
Vertical
45°