A waveguide section in a microwave circuit acts as

For ideal dielectric loss angle is zero. For good quality cables, loss angle is very small, about 1° only.

Printed circuit techniques is used for micro strip line.

Since all ports matched, input SWR = 1. No power is reflected and P_in = P₄ = 1 W.

This power splits between ports 1 and 2. Therefore P₁ = P₂ = 0.5 ?, P₃ = 0.

Skin effect increases as frequency increases.

It is somewhat similar to TWT and can deliver microwave power over a wide frequency band.

It has an electron gun and a helix structure. However the interaction between electron beam and RF wave is different than in TWT.

The growing RF wave travels in opposite direction to the electron beam.

The frequency of wave can be changed by changing the voltage which controls the beam velocity.

Moreover the amplitude of oscillations can be decreased continuously to zero by changing the beam current.

It features are:

1. Frequency range - 1 GHz to 1000 GHz.

2. Power output - 10 mV to 150 mW (continuous wave) 250kW (pulsed).

It is used as signal source in transmitters and instruments.

A quarter wave line o.c. at far end behaves as a series tuned circuit.

Artificial transmission lines have many applications. One of the applications is to simulate an actual line in the laboratory.