Waveguide

Waveguide is the type of transmission line which carries microwave frequencies from source to load. The energy is in the form of electric field and magnetic field which are perpendicular to each other the electric field and magnetic field inside. The waveguide is also perpendicular to the direction of propagation as the energy is in the form of electric/magnetic field. Therefore, it is capable to handle the high power of micro wave length of frequencies.

Types of Wave guide:

There are the basic two types of the wave guide.

1. Circular wave guide
2. Rectangular wave guide

Construction:

1. Circular wave Guide:

   As shown in the given diagram the circular waveguide is designed from a conducting pipe which is hollow from the center and polished from interior portion. The outer surface of the wave guide is coded with the insulated paint in order to avoid dust and rust. These types of wave guide are available in different lengths and sizes in order to fulfill the requirement of the circuit.

2. Rectangular Wave Guide:

   As shown in the given diagram, the rectangular wave guide is designed from conducting material in rectangular shape which is hollow from the center and fully polished from interior. The outer surface of the waveguide is coded with insulating material or paint in order to avoid dust and rust. These types of wave guides are available in different lengths and sizes in order to fulfill the requirements of the circuit.

Direction of Propagation:

As shown in the given diagram, there are two dimensions of the rectangular waveguide where one is the broad dimension and the second is the narrow dimension. The broad dimension is denoted by “a” and the narrow is by “b”. In the wave guide the electric-field and the magnetic-field carry the signal from source to load. In this case electric-filed and the magnetic-field is perpendicular to each other and at the same time. These fields are perpendicular to the direction of propagation. Inside side the wave guide horizontal field is perpendicular to “a” and Vertical field is perpendicular to “b” according to the frequency both Horizontal and Vertical fields changes its amplitudes and direction as shown in the diagram.

Uses of Wave Guide:

There are the following uses of Wave Guide.

1. It is used where the transmission or reception is in the range of microwave frequencies.
2. It is also used for handling the high power of energy.
3. It is mostly used in the airborne radar.
4. In ground radar’s we also use the wave guide.
5. The circular wave guide is mostly used in the ground radar to transmit or receive the energy from antenna. Which revolves in 360o bearing continuously.
6. The wave guide is also used in communication system.
7. In satellite communication the wave guide is mostly used.
8. We also use the wave guide in the devices of navigation aids.
9. In some cases the wave guide is used as attenuator where very high frequencies are involved.
10. The wave guides are also used with the cavity resonators to carry the input and out put signals.

Flexible Waveguide

It is the type of waveguide which can be easily turn and twisted in circuits to connect the source with the load. This type of wave guide is designed in such a way that internal portion is made of conducting material in spring shape. The external portion is covered with the rubber to avoid dust, rust and humidity.

Uses of Flexible waveguide

1. The flexible waveguide is used in such microwave equipment’s where the path from load to the source is twisty.
2. This waveguide is also used to minimize the size and design of the microwave equipment’s.
3. We also used the flexible waveguide to reduce the weight due to reduction in size and to reduce the space occupied by the microwave equipment’s.

Higher Mode

It is the mode of operation which deals with the high range of frequency. The higher mode is from 30 MHz to 300 MHz in the higher mode the transmission or propagation is carried out through the waveguide in form of electromagnetic and horizontal field. TE mode and TM mode are higher modes.

Lower Mode

The mode of operation which deals with the frequency less than 3 MHz is called the lower mode. In this case the transmission is carried out through the micro strip coaxial cable. The movement of electrons for the flow of current is taken in the lower mode of operation to carry the energy from the source to load.