Experiment 1
Detector Angle
Signal Level (mA)
-90
0 mA
-80
0 mA
-70
0.6 mA
-60
2.4 mA
-50
3.6 mA
-40
5.4 mA
-30
6.6 mA
-20
7.8 mA
-10
8.4 mA
0
9 mA
10
8.4 mA
20
7.2 mA
30
6.6 mA
40
5.7 mA
50
3.6 mA
60
2.4 mA
70
0.6 mA
80
0.3 mA
90
0 mA
Experiment 2
Polarizer angle
Signal Level
0
11.4 mA
22.5
3 mA
45
2.4 mA
67.5
1.2 mA
90
0 mA
Experiment 3
Polarizer Angle
Signal Level
0
0 mA
45
1.8 mA
90
0 mA
Experiment 4
Initial reflector location: __160cm= 1.60 m_____________
Final reflector location: ___147.3 cm = 1.473 m____________
Observed wavelength: _.635m______________
Theoretical wavelength: _c/f= .855 m______________
(Assume that f = 10.525 GHz.)
Percent error : 25.7 %
(Assume theoretical wavelength is correct.)
1. If the detector readings are proportional to the amplitude of the microwave E field, the data
from the first polarization experiment should be proportional to cos(θ) where θ is the angle
between transmitter and detector. If the readings are proportional to the energy stored in the
E field, the readings should be proportional to cos2(θ). Based on your data, are the detector
readings proportional to amplitude, energy, or neither?
The detector readings are proportional to cos^2, which means the readings are proportional to
the energy stored.
2. The simplest design for a radio/microwave transmitter antenna is a vertical conducting rod
about one quarter-wavelength long. A mobile-phone manufacturer wants to build such an
antenna into a GSM-900 (900 MHz) phone. How small can the phone be?
Lambda = c/f = 3*10^8 / 900*10^6 = 33.3cm
L = lambda/4 = 8.33 cm
The phone can be 8.33 cm long.
3. For aerodynamic reasons, nearly all modern aircraft feature at least
one large vertical stabilizer. The B-2 “stealth” bomber pictured to the
right, however, has no vertical fins at all. Why not?
The vertical fin is not required to fly, it is only there for stability. The stability is not needed in the
stealth bomber, so it does not have a vertical fin.
4. TV stations in the U.S. normally broadcast horizontally-polarized
signals. Is this TV antenna mounted correctly, or should it be rotated?
The TV antenna should not be rotated, since in its horizontal position it will receive the maximal
signal strength.