Experiment 2 : Measuring of Guide Wavelenght, l_H

            

           

Wavelength in free space is given by: l_o = c / f . Where c is the velocity of propagation of electromagnetic waves in free space and f is the wave frequency. Calculation of guide wavelength, l_H, is base on the formula:

 

l_H = l_o / Ö [1- (l_o /2a)²]          ----------------------------------------- (1)

 

Since the experiment is occupying waveguide type WR 62, a is chosen to be 15.8 mm where a is the waveguide broadside and l_o is free space wavelength. For measuring the guide wavelength, the line is terminated with a variable sliding short circuit with strong mismatching. The strong mismatching of the waveguide train forms standing waves, the maximum and minimum of which represent the guide wavelength. The length between the two maximum, l /2, is measured and hence, the wavelength in the waveguide, l_H is calculated. Figure 4 shows the curve of the voltage maximum at different mismatches.

      

 

                              

               

Figure 4: Voltage curve at different mismatches.