how do EM waves propagate

[E=MC2]

how do EM waves propagate through the atmosphere?

what does the E component and the M component do?

what is the effect of the medium through which the wave is travelling?

why do low freq EM waves bend easily?

why do high freq EM travel in line of sight?

 

[flatulent]

The bending part is easy to answer. They do not bend unless the properties of the media they go through changes with position. Some of the properties are caused by the physical movement of charged particles. They cannot move in synchronism with the field of higher frequency signals. That is why the E and F layers of the ionosphere have a maximum frequency where the waves will not be reflected, but go right through.

 

[Moss]

WOW! Simple qustions!

why do high freq EM travel in line of sight?

why do low freq EM waves bend easily?

The main reason for nonlinear propagation of EM waves is difraction. Difraction is process that waves bend arround a obstacle( or hole) with linear dimensions comparable with the wavelenght of EM. Lower frequency corespond to biger wavelenght. For example 1GHz wave has wavelenght of 30cm, and 1MHz wave has wavelenght of 300m. Thats LF EM waves why bends around hills, buildings, and higher frequency waves

what is the effect of the medium through which the wave is travelling?

Basiclly there are two effects. First one is delay, because EM wave travels with speed arround 3exp8 (300000000m/sec) in free space ( vacuum or air). Second is attenuation, wich is depends from:
1.expanding front of electromagnetic wave.
2.absobtion in water and other gas molecules:

what does the E component and the M component do?

They represent electric and magnetic component of EM field.

how do EM waves propagate through the atmosphere?

Time varying electric fields moving through the space, produce magnetic fields that also changing ( with same speed, frequency). This magnetic fields in turn produce electric fields. Thats why EM waves can propagate even in spaces that there are no any electrical or magnetic particles.

They do not bend unless the properties of the media they go through changes with position

This is so called "refraction" . Other major way of nonlinear propagation is difraction.


For beter understanding I will advice you to read some book like entry level colledge physics or etc.
Good luck!

 

[djalli]

what does the E component and the M component do?

They represent electric and magnetic component of EM field.

Moss said it right, they are but what they do was the question? To make it simplier they do complement each other.

Remember rule of thumb, there is not EM wave without one of the component! Maybe one is smaller than other but none of them is ever zero otherwise we can not talk for EM wave!

Their ratio is a useful quantity. In free space this quantity is a real number of 377ohms.

 

[kukitron]

EMI!!!

EMI is the headach of any hardware designer, and usually it requirs more intuition and experience than knowledge.

A small rule of tumb, increase the area of contact for uncover metal parts that could posible generate emissions,

Cheers

 

[mazelk]

EM waves are created by a particle packets (e.g.: electrons) that change their velocity due to any boundary effect (e.g.: crossing material boundaries)

how do EM waves propagate through the atmosphere?

why do low freq EM waves bend easily?

why do high freq EM travel in line of sight?

High frequency EM wave has more energy, and it has more directivity.