Manual

Characteristics of Reflex Klystron

Aim:

To study the Node characteristics of a Reflex Klystron source.

Apparatus Required:

1.Reflex Klystron power supply2.Reflex Klystron source3.Isolator4.Attenuator5.Frequency Meter6.Slotted Line section7.Detector8.CRO

Procedure:

Initial Settings:

1. Ensure that the Beam voltage is minimum and the Repeller voltage is maximum before switching on the power supply.

2. Amplitude of AM modulation should also be set at minimum condition.

3. After switching on the power supply, set the Beam voltage to 260V and Repeller voltage to about 70V.

4. Set the modulation to AM 5. Also set the amplitude of the AM knob to maximum

position.6. Release the attenuator knob such that it is at minimum

attenuation position.7. Tune the knob in the slotted line section and adjust the

same to get maximum square wave output.

Experiment:

1. Now vary the repeller voltage and note down the output voltage and the corresponding dip frequency.

2. Continue until you have noted three distinct Modes.3. Plot the graph

(i) Repeller voltage versus o/p voltage.(ii) Repeller voltage versus Dip frequency.

Block Diagram:

Tabular Column:

Characteristics of Reflex Klystron

Repeller Voltage (V) Output Power(W) Dip Frequency(GHz)

Reflex Klystron Power Supply

Reflex Klystron Source

Frequency Meter

Attenuator

Slotted Line Section

Detector

CRO

Isolator

Study of Gunn Diode Characteristics

Aim:To study the voltage-current and the attenuation

characteristics of Gunn Diode.

Apparatus Required:1) Gunn Diode and Power Supply2) PIN Modulator3) Isolator4) Attenuator5) Frequency Meter6) Slotted Line Section7) Detector8) CRO Procedure:Initial Settings:

Gunn Diode Setupi) Before switching on the main switch, ensure that all

knobs in Gunn power supply is in zero position.ii) Ensure that the attenuation knob is in minimum

position.

iii) Switch on the main power supply and set the Gunn voltage to 7V and modulation at AM.

iv) Keep the modulation frequency and PIN bias knob in maximum position.

Experiment:

To measure VI Characteristics:

i) Vary the Gunn bias voltage in the steps of 0.5V upto 7V and measure the corresponding current value.

To measure attenuation Characteristics:

i) For various values recorded in the attenuator measure the corresponding o/p voltage in CRO.

ii) Attenuation is varied with the help of screw gauge in attenuator.

Block Diagram:

Tabular Column:

VI Characteristics Attenuation Characteristics

Voltage(V) Current(A) Distance(mm) O/p Voltage(V)

Gunn Diode Power Supply

Gunn Source

Attenuator

Isolator

Frequency Meter

Slotted Line

Section

Detector

PIN Modulator

CRO

Result:Thus the VI and attenuation characteristics of the Gunn Diode are studied.

Vp=Vv=

VSWR, FREQUENCY AND WAVELENGTH MEASUREMENT

Aim:To measure the frequency and the wavelength of the

microwave signal and also to measure VSWR at various loads.

Apparatus Required:1) Reflex Klystron Power Supply2) Reflex Klystron Source3) Isolator4) Frequency Meter5) Attenuator6) Slotted Line Section7) Detector8) CRO

Procedure:Initial Settings:

i) Before switching on the main switch, ensure that all knobs in Klystron power supply is in zero position.

ii) Ensure that the attenuation knob is in minimum position.

iii) Switch on the main power supply and set the voltage to 7V and modulation at AM.

iv) Keep the modulation frequency and PIN bias knob in maximum position.

EXPERIMENT:

To measure VSWR:

i) The carriage of the slotted line section is moved in order to get the first minima and maxima and note down the values of Vmax,Vmin.

ii) Now without disturbing the setup, replace the detector with various loads and note down its corresponding Vmax and Vmin and hence calculate VSWR using the formula. VSWR = (Vmax/Vmin)

To measure Frequency and Wavelength:

i) By adjusting slotted line section knob,measure the distance between adjacent maxima and minima.

ii) Double the distance between the minimas/maximas gives the Guided wavelength.

iii) Calculate the wavelength of the microwave signal using the formula

iv) Calculate the corresponding frequency using the formulaft =c/λo

Block Diagram:

Tabular column:VSWR Measurement

S.No Loads P max P min VSWR=Pmax/

Reflex Klysrton Power Supply


Attenuator

Isolator

Frequency Meter

Slotted Line

Section

Detector

CRO

(W) (W) Pmin

1 Matched Termination

2 Horn antenna

3 Movable slot

4 Isolator

5 Circulator

Frequency and Wavelength Measurement

Direct Frequency Reading (GHz)

D1(cm)

D2(cm)

λg=2(D1-D2)(cm)

1/λo(1/cm)

Ft=c/λo(GHz)

Result:

Thus the VSWR, wavelength and the frequency of a microwave source are measured.Frequency theoretical= ; Frequency practical= ; Wavelength theoretical= ; Wavelength practical= ;

E PLANE TEE, H PLANE TEE AND MAGIC TEE

Aim:To measure the distribution of microwave power in E

Plane Tee, H Plane Tee and Magic Tee.

Apparatus Required:1) Reflex Klystron Power supply2) Reflex Klystron source3) Isolator4) Frequency Meter5) Attenuator 6) Slotted section7) E Plane ,H Plane and Magic Tees.8) Detector

9) CRO

Procedure:Initial Settings:




4. Set the modulation to AM 5. Also set the amplitude of the AM knob to maximum position.6. Release the attenuator knob such that it is at minimum attenuation

position.7. Tune the knob in the slotted line section and adjust the same to get

maximum square wave output.

Experiment:

1. Mount the E – plane Tee after the slotted line section and measure the output at two arms when the input is given to third arm.

2. Repeat the same for all the available combinations of the arm.3. Repeat the above two steps for H – plane Tee and also Magic Tee4. Calculate the insertion loss and coupling coefficient using the

formula,

Insertion loss, Iij = 10 log ( Pi / Pj)

α1= (I12 + I21) / 2 ; α2= (I23 + I32) / 2 ; α3= (I13 + I31) / 2

Coupling Coefficient, C = 10 ( - α / 20)

Block diagram:

TABULAR COLUMN:

E – Plane TEE:

Input Port(Pi) Power at input(W)

Output Port(Pij)

Power at Output(W)

Insertion loss( dB)

Port 1 Port 2 I12=

I13=Port 3

Port 2 Port 1 I21=

I23=Port 3



Attenuator

Isolator

Frequency Meter

Slotted Line

Section

Detector

CRO

Port 3 Port 1 I31=

I32=Port 2

H – Plane TEE:


Output Port(Pij)

Power at Output(W)

Insertion loss( dB)

Port 1 Port 2 I12=

I13=Port 3

Port 2 Port 1 I21=

I23=Port 3

Port 3 Port 1 I31=

I32=Port 2

Magic TEE:


Output Port(Pij)

Power at Output(W)

Insertion loss( dB)

Port 1 Port 2 I12=

I13=

I14=

Port 3

Port 4

Port 2 Port 1 I21=

I23=

I24=

Port 3

Port 4

Port 3 Port 1 I31=

I32=

I34=

Port 2

Port 4

Port 4 Port 1 I41=

I42=

I43=

Port 2

Port 3

Result:Thus the s-matrix of the E plane Tee , H plane Tee and

Magic Tee are characterized.

Isolator and Circulator – S – Parameter Measurements

AIM: To characterize the S – matrix of an isolator and circulator.

APPARATUS REQUIRED:

1.Reflex Klystron power supply2.Reflex Klystron source3.Isolator4.Attenuator

5.Frequency Meter6.Slotted Line section7.Detector8.CRO

PROCEDURE:

Initial Settings:




4. Set the modulation to AM 5. Also set the amplitude of the AM knob to maximum position.6. Release the attenuator knob such that it is at minimum attenuation

position.7. Tune the knob in the slotted line section and adjust the same to get

maximum square wave output.

Experiment:

1. Mount the isolator and note the output at its output port (port2).2. Repeat the above steps for all possible combinations of port inputs.3. Repeat the experiment by replacing the isolator by a circulator.4. Calculate the S – matrix.

Block Diagram :



Frequency Meter

Attenuator Slotted Line Section

Detector

CRO

Isolator

Tabular Column:

Circulator Isolator

Ports Output Power(mW)

Ports Output Power(mW)

RESULT: Thus the S – matrix of microwave isolator and circulator is characterized successfully.

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