lab sheet microwave devices emg 2026 - Faculty of Engineering ...

Microwave Devices Faculty of Engineering EMG2026
Appendix A
Microwave Frequency Measurement Using Slotted-line Probe
1. Adjust the variable attenuator to obtain an SWR greater than 3.
2. Move the probe along the waveguide to find two successive minimum points. Record the positions of
these two points (x 1 and x 2 ) from the Vernier scale of the slotted-line waveguide. Determine the
waveguide wavelength λ g .
Power
λ g = 2d
x1
d
x2
Distance
Fig. A1: Standing wave pattern.
3. Calculate the free-space wavelength λ o using equation A1. The inner dimensions of the waveguide is
given as a=2.2870cm and b=1.0160cm. The cutoff waveleght for TE 10 mode is λ c = 2a.
1 1 1
2
=
2
+
2
(A1)
λ λ λ
o g c
4. Calculate the microwave frequency f o = c/λ o .
Revision Sept 2010