Radio Frequency and Microwave Engineering

All Q&A

Write short note on Magnetron Oscillator.

3 December, 2024

The magnetron cross section view and field distribution inside the magnetron are presented in Fig. 38(a) and 2 respectively. The reason behind the development of magnetron tube was the requirement of high power during the time of 2nd world war though it was invented by Hull in 1921. The basic structure of a magnetron is a number of identical resonators arranged in a cylindrical pattern around a cylindrical cathode.

What is a slow wave structure? Why does the TWT need such a structure? Explain the beam and RF interaction in such wave tube.

3 December, 2024

The slow wave structures are a special type of circuits, used in microwave tubes to reduce the wave velocity in a certain direction so that a prolonged interaction between the electron beam and the signal wave may take place.

Compare and contrast the bunching operation in a two cavity klystron and reflex klystron.

3 December, 2024

The Klystron tube operates on the principle of velocity modulation instead of current density modulation employed in conventional tubes. The idea of Klystron Amplifier was introduced by Varian brothers in 1939. The typical diagram of two cavity Klystron amplifier is depicted in Fig. 31. It consists of electron gun, buncher cavity, catcher cavity and collector. Electrons emitted by the cathode are focused by one or more focusing electrodes kept in front of the cathode.

With the neat sketch, explain working principle of a two – hole directional coupler. Derive the scattering matrix of magic Tee. A multi hole directional coupler is fed with single power of 2.8 mW at 10 GHz. The coupling factor is 3 dB and the directivity is better than 40 dB over X-band range. Find the distribution of power at all other ports.

3 December, 2024

The ideal two holes coupler is depicted in Fig. 5. It consists of two guides the main and the auxiliary with two tiny holes between them as shown in Fig. 5. The two holes are separated from each other by the distance

What is IMPATT diode? How does the negative resistance arise in this diode?

3 December, 2024

It is possible to make a microwave diode exhibit negative resistance by having a delay between voltage and current in an avalanche together with transit time through the material. The IMPATT diode is stand for Impact Ionization Avalanche Transit Time Device.

What is Gunn diode oscillator? What are different modes of operation of Gunn diode? Mention its applications.

3 December, 2024

A Gunn diode oscillator circuit consists of a resonant cavity. An arrangement for coupling diode to the cavity, a circuit for biasing the diode and a mechanism to couple the R.F power the diode and a mechanism to couple the R.F power from the cavity to the external circuit or load.

What is E-plane Tee? Derive its S-matrix.

3 December, 2024

E-plane tee is a three port network. Here the auxiliary or side arm axis is parallel t the plane of the electric field of the main guide and hence this tee is known as E –plane Tee.

Subjects

Analog Communication Electrical Engineering Management Power Electronics Basic Electrical Engineering

Browse Streams