EXPERIMENT 1 MEASUREMENT OF FREE SPACE WAVELENGTH AND GUIDE WAVELENGTHAim: To determine the Free Space Wavelength and Guide Wavelength using a microwave trainer.Objective:To measure guide wavelength & frequency of a signal in a rectangular wave guide.To understand the relationship between the wave guide and the free spaceTo analysis the effect of increase or decrease the operating frequency on the wave guides. Equipment and Components required:Gunn Power Supply.
Square wave Oscillator.Gunn Oscillator.PiN Modulator.Variable Attenuator.Frequency Meter.Slotted line with detector probe.Wave guide section.Display Unit (CRO).
Reflecting plate Short.Experimental Set-up:4178398295910CRO00CRO-351790212090Power Supply00Power Supply746125197485Square wave Oscillator00Square wave Oscillator4615034133985115379513335-9525107956515100153719005276215181610Wave guide section00Wave guide section4175760226695Slotted line00Slotted line3051810215265Frequency Meter00Frequency Meter1891030182245Variable Attenuator00Variable Attenuator746760180975PiN Modulator00PiN Modulator-405765143510Gunn Oscillator00Gunn Oscillator5045710188595003918585242570002758538242277004648201898650016414752254250063744232634270614489512446000 Reflecting plate Procedure:Connect the Pin wire modulator from the device to the CRO to apply 1 KHz, and 2 p-p. make the variable attenuator equal 10 dB. Turn on the Gunn power supply, change voltage from power supply to be appropriate full scale (p-p). Make the frequency oscillation equal to 9GHz.Set the Gunn power supply and show a clear square wave in the power supply on the CRO.
Move the frequency meter until there is drop in the signal level. Record the reading that show from the frequency meter in the table.Start measure the wavelength; put the reflecting plate perpendicular to the waveguide.Move the reflecting plate, the CRO shows the first minimum and second minimum waves and measure the distance by the ruler.
Close the wave guide by the shorting plate and measure the distance between two adjacent NULL by the slotted line.Observation:Measured Frequency (GHz) Calculated frequency (GHz) Measured ?o ?o = 2(d2 – d1) (cm) Calculated ?o (cm) Measured ?g ?g = 2(dS2 – dS1) (cm) Calculated ?g (cm)11.260 GHz 11.26 GHz d1=1.6 cmd2=2.
9 cm?o=2.6 cm ds1 = 0.4 cm ds2 =2 cm?g =3.2cm -326.642× 10 m -332.827×10 mSkill Drill:Change the operating frequency and analyze the effect in the wavelength.Measured Frequency (GHz) Calculated frequency (GHz) Measured ?o ?o = 2(d2 – d1) (cm) Calculated ?o (cm) Measured ?g ?g = 2(dS2 – dS1) (cm) Calculated ?g (cm)10.
34 GHz 9 GHz d1=0.6 cmd2=2 cm?o=2.8 cm ds1 = 0.8 cm ds2 =1.
3 cm?g =1 cm -329× 10 m -348.75 × 10 mResult & Analysis:Measured the free and find the distance of two minimum waves. Calculated the ?o by the formula of the two distances, values range from 0.4 n 3.2 cm .
Than calculated the ?g by given formula. Next change the operating frequency to analyze the effect in the wavelength. Measured Frequency equal to 10.34 GHz and the calculated frequency equal to 9GHz. Repeat the same step to calculate the ?o and ?g by the given formula the values range from 0.
6 and 2.8 . Those values shows the effect of the frequency on the wavelength where a larger frequency means a smaller wavelength.Discussion & Conclusion:In conclusion, understand the microwave trainer uses. Also how to measure the distance of the wave length of free space and getting the minimum waves.
Than measure the minimum wave length of the wave guides by the slotted line and calculate the distance. After that analyze the effect of the frequency on the wavelength which is increasing the frequency means decreases on the wavelength. We use it in the applications of our daily lives without knowing how its work. Use it in microwave communications, broadcasting, and radar installations.