Klystron Microwave Test Bench | Gunn Microwave Test Bench
This page describes Klystron Microwave test bench and Gunn oscillator Microwave test bench. The block diagrams and explains components or modules used in these microwave test benches.
Introduction: The typical microwave test bench are precision microwave systems. It consists of rectangular microwave waveguide components. They are used for test and measurement of various microwave modules in the lab. Let us understand klystron and gunn oscillator based microwave test benches.
Klystron Microwave Test Bench block diagram with components
The figure-1 depicts klystron microwave test bench. It consists of
klystron power supply, klystron mount tube, isolator, variable attenuator, frequency meter,
slotted line section, VSWR meter and load. Let us understand functions of each in brief.
• Klystron power supply: It helps in operating low power klystron (e.g. 2K25). It houses AM modulation, FM modulation and external modulating signal functionalities. It usually provides display for beam voltage, beam current and repeller voltage.
• Klystron mount tube : This consists of reflex klystron. It uses velocity modulation in order to transform continuous electron beam into corresponding microwave power.
• Isolator: It passes microwave signal only in one direction and blocks signal going in the other direction.
• Variable attenuator: It is used to attenuate microwave signal with variable attenuation settings as made by the user. The different attenuation can be set.
• Frequency meter: It is used for frequency measurement.
• Slotted line section: It should cover desired frequency and should be equipped with accurate scale/indicator.
• VSWR meter: It is used for standing wave measurement with suitable detector and slotted line (or waveguide) section. It is used to measure VSWR or SWR. It is designed such that it avoids harmonics of line frequency.
• Load: It is microwave matched termination at desired characteristic impedance either 50 or 75 ohm. It is used to absorb microwave power.
Gunn Microwave Test Bench block diagram with components
The figure-2 depicts Gunn microwave test bench. It consists of
• Gunn Power Supply:
• Gunn Oscillator:
• PIN modulator:
• Variable attenuator:
• Detector Mount:
• SWR meter:
The setup shown is used for PC to PC communication.
Following procedures are followed in the lab to conduct this experiment.
• Make the setup as shown and install communication software in both PCs.
• Connect interfacing cables as required from both PCs to the microwave test bench.
• Switch ON PC sitch from rear of SWR meter.
• Switch ON gunn power supply with setting of 10Volt.
• Select appropriate COM ports and start communication.
• Adjust comparator and potentiometer to get the output.
TWT and Klystron related links
SSPA Test Procedure
Power Amplifier Basics and SSPA design example
Reflex Klystron Calculator
TWTA vs SSPA-Difference between TWTA and SSPA