Electronics and Communication Engineering - Microwave Communication

Transmission coefficient = 1.265 ∠- 18.43°.

It uses a single cavity resonator for generating microwave oscillations.

Its parts are electron gun, resonator, repeller and output coupling.

It operates on the principle of positive feed back.

The repeller electrode is at negative potential and sends the partially bunched electron beam back to resonator cavity.

This positive feedback supports oscillations. Its feature are:

1. Frequency range - 2 to 100 GHz

2. Power output - 10 MW to about 2 W

3. Efficiency - 10 - 20 %

Its applications include radar receivers, local oscillator in microwave devices, oscillator for microwave measurements in laboratories etc.

A quarter wave line short-circuited at far end behaves as a parallel tuned circuit.

A short-circuited stub is a suitable method of matching.

Beam width between nulls of a parabolic antenna . Therefore 50° is the nearest value.