Waveguide

A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave. Most common one is a hollow conductive metal pipe used to carry high frequency radio waves, particularly microwaves.

A waveguide can be almost any shape. The most popular shape is rectangular, but circular and even more exotic shapes are used.

When using waveguide bends and waveguide twists, it is necessary to ensure the bending and twisting is accomplished in the correct manner otherwise the electric and magnetic fields will be unduly distorted and the signal will not propagate in the manner required causing loss and reflections.

There are several ways in which waveguide bends can be accomplished:

H bend is used to change the physical direction of propagation. It derives its name from the fact that the H lines are bent in this transition. While the E lines remain vertical for the dominant mode.

E bend, the choice between an E or H bend is normally governed by mechanical considerations because neither produces large discontinuities if the bends are gradual enough.

A Twist section is used to change the plane of polarization of the wave.

A shunt tee is so named because of the side arm shutting of the E field for TE modes.

The series tee is often used for impedance matching just as the single -stud tuner is used for transmission lines.

Pulse repetition frequency is the number of radar pulses transmitted per second.

Pulse repetition time is the time from the beginning of one pulse to the beginning of the next.

The time between pulses is called rest time or receiver time.

A radar mile is equal to 2000 yd., or 6000 ft.

Double range echoes are produced when the reflected beam makes a second trip.