A pulsed radar produces 1 ? sec pulses at a rate of 1000 per second. The duty cycle is

Z₀₁ provides series inductances and teflon filled low impedance line Z₀₂ provides shunt capacitance.

Coplanar arms are decoupled.

Time required for microwave cooking is much less than the time required for conventional cooking.

PIN diode is not used in oscillators.

A PIN diode has an intrinsic (i) layer between p and n layers. When reverse bias is applied depletion layers are formed at p-i and i-n junctions.

The effective/width of depletion layer increases by the width of i layer. It can be used as a voltage controlled attenuator.

At high frequencies the rectification effect ceases and impedance of diode is effectively that of i layer.

This impedance varies with the applied bias. It is used in high frequency switching circuits, limiters, modulators etc.

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.

Varactor diode is used in all the three applications.

or .

If line is s.c |r_v| = 1 and VSWR = ?.